US20100327150A1 - Multimode planar waveguide spectral filter - Google Patents
Multimode planar waveguide spectral filter Download PDFInfo
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- US20100327150A1 US20100327150A1 US12/785,950 US78595010A US2010327150A1 US 20100327150 A1 US20100327150 A1 US 20100327150A1 US 78595010 A US78595010 A US 78595010A US 2010327150 A1 US2010327150 A1 US 2010327150A1
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- G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
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Definitions
- the field of the present invention relates to optical devices incorporating distributed optical structures.
- multimode planar waveguide spectral filters are disclosed herein.
- a spectral filter comprises a planar optical waveguide having at least one set of diffractive elements.
- the planar optical waveguide substantially confines in one transverse spatial dimension an optical signal propagating in two other spatial dimensions therein.
- the planar waveguide supports multiple optical transverse modes in the confined transverse dimension.
- Each diffractive element set routes, between a corresponding input optical port and a corresponding output optical port, a corresponding diffracted portion of the optical signal propagating in the planar waveguide that is diffracted by the diffractive element set.
- the corresponding diffracted portion of the optical signal reaches the corresponding output optical port as a superposition of multiple optical transverse modes supported by the planar optical waveguide.
- a corresponding multimode optical source may be positioned and aligned so as to launch the optical signal into the planar waveguide, through the corresponding input optical port, as a superposition of multiple optical transverse modes supported by the planar optical waveguide.
- a corresponding multimode output waveguide may be positioned and aligned so as to receive, through the corresponding output optical port, the corresponding diffracted portion of the optical signal.
- Multiple diffractive element sets may route corresponding diffracted portions of optical signal between one or more corresponding input optical ports and one or more corresponding output optical ports.
- FIGS. 1A and 1B are side and top schematic views, respectively, of a planar waveguide spectral filter.
- FIG. 1C is a schematic top view showing an optical path between input and output optical ports of a planar waveguide spectral filter.
- FIGS. 2A and 2B are side schematic views of planar waveguide spectral filters.
- FIG. 3 is a side schematic view of a planar waveguide spectral filter.
- FIG. 4 illustrates the dependence of mode angle on planar waveguide thickness parameter.
- FIG. 5 illustrates the dependence of fractional bandpass on cladding index for a planar waveguide spectral filter.
- a spectral filter comprises a multimode planar optical waveguide having at least one set of diffractive elements.
- the planar optical waveguide substantially confines in one transverse dimension optical signals propagating in the other two spatial dimensions.
- the planar waveguide supports multiple transverse optical modes in the confined transverse dimension.
- An optical signal propagates through the multimode planar optical waveguide as a superposition of the supported optical modes.
- the relative phases of the modes of such a superposition generally vary with propagation distance through the waveguide, since the optical modes propagate at differing phase velocities (i.e., the waveguide exhibits modal dispersion).
- the planar waveguide typically comprises a core (a two-dimensional sheet or layer) surrounded by lower-index cladding.
- the core is fabricated using one or more dielectric materials substantially transparent over a desired operating wavelength range.
- one or both claddings may be vacuum, air, or other ambient atmosphere. More typically, one or both claddings comprise layers of dielectric material(s), with the cladding refractive indices n 1 and n 2 typically being smaller than the core refractive index n core .
- the cladding indices might be larger than the core index while still enabling the planar waveguide to support guided, albeit lossy, optical modes.
- the planar waveguide may be secured to a substrate, for facilitating manufacture, for mechanical support, and/or for other reasons.
- the set of diffractive elements of the spectral filter may also be referred to as: a set of holographic elements; a volume hologram; a distributed reflective element, distributed reflector, or distributed Bragg reflector (DBR); a Bragg reflective grating (BRG); a holographic Bragg reflector (HBR); a directional photonic-bandgap structure; a mode-selective photonic crystal; or other equivalent terms of art.
- DBR distributed reflective element, distributed reflector, or distributed Bragg reflector
- BRG Bragg reflective grating
- HBR holographic Bragg reflector
- Each diffractive element of the set diffracts reflects, scatters, or otherwise redirects a portion of an incident optical signal (said process hereinafter simply referred to as diffraction).
- Each diffractive element of the set typically comprises some suitable alteration of the planar waveguide (ridge, groove, index modulation, density modulation, and so on), and is spatially defined by a virtual two-dimensional curvilinear diffractive element contour, the curvilinear shape of the contour typically being configured to impart desired spatial characteristics onto the diffracted portion of the optical signal.
- the curvilinear diffractive elements of the set (or equivalently, their corresponding contours) are spatially arranged with respect to one another so that the corresponding portions of the optical signal diffracted by each element interfere with one another, so as to impart desired spectral and/or temporal characteristics onto the portion of the optical signal collectively diffracted from the set of diffractive elements.
- the diffractive elements in the set are arranged so that an input optical signal, entering the planar waveguide through an input optical port, is successively incident on diffractive elements of the set. A fraction of the incident amplitude is diffracted by a diffractive element and the remainder transmitted and incident on another diffractive element, and so on successively through the set of diffractive elements.
- the diffractive elements are therefore spaced substantially longitudinally along the propagation direction of the incident optical signal (in contrast to a traditional surface grating, in which the diffractive elements, i.e. grating lines, are spaced transversely across the wavefront of a normally incident optical signal).
- Each curvilinear diffractive element is shaped to direct its diffracted portion of the optical signal to an output optical port, typically propagating back through earlier diffractive elements of the set.
- the relative spatial arrangement (i.e. longitudinal spacing) of the diffractive elements of the set yields desired spectral and/or temporal characteristics for the overall diffracted optical signal reaching the output optical port.
- optical ports may be defined structurally (for example, by an aperture, waveguide, fiber, lens, or other optical component) and/or functionally (i.e., by a spatial location, convergence/divergence/collimation, and/or propagation direction).
- a set of diffractive elements may be arranged to yield an arbitrary spectral transfer function (in terms of amplitude and phase).
- modal dispersion and mode-to-mode coupling of diffracted portions of the optical signal limit the range of spectral transfer functions that may be implemented.
- the set of diffractive elements of the spectral filter provides dual functionality, spatially routing an optical signal between an input optical port and an output optical port, while at the same time acting as a spectral filter.
- the curvilinear diffractive elements may be designed (by computer generation, for example) so as to provide optimal routing, imaging, or focusing of the optical signal between an input optical port and a desired output optical port, thus reducing or minimizing insertion loss of the spectral filter.
- Simple curvilinear diffractive elements (segments of circles, ellipses, parabolas, hyperbolas, and so forth), if not optimal, may be employed as approximations of fully optimized contours.
- a wide range of fabrication techniques may be employed for forming the diffractive element set, and any suitable technique(s) may be employed while remaining within the scope of the present disclosure and/or appended claims. The following are exemplary only, and are not intended to be exhaustive.
- Diffractive elements may be formed lithographically on the surface of a multimode planar optical waveguide, or at one or both interfaces between core and cladding of a multimode planar optical waveguide.
- Diffractive contours may be formed lithographically in the interior of the core layer and/or a cladding layer of the planar optical waveguide using one or more spatial lithography steps performed after an initial partial deposition of layer material.
- Diffractive elements may be formed in the core and/or cladding layers by projecting ultraviolet light or other suitable radiation through an amplitude and/or phase mask so as to create an interference pattern within the multimode planar waveguide (fabricated at least in part with suitably sensitive material) whose fringe contours match the desired diffractive element contours.
- the mask may be zeroth-order-suppressed according to methods known in the art, including the arts associated with fabrication of fiber Bragg gratings.
- the amplitude and/or phase mask may be produced lithographically via laser writer or e-beam, it may be interferometrically formed, or it may be formed by any other suitable technique.
- a larger scale mask may be produced and reduced to needed dimensions via photoreduction lithography, as in a stepper, to produce a mask at the needed scale.
- Diffractive elements may be formed by molding, stamping, impressing, embossing, or other mechanical processes.
- a phase mask may be stamped onto the core or cladding surface followed by optical exposure to create diffractive elements throughout the core and or cladding region.
- the optical or UV source used to write the diffractive elements in this case should have a coherence length comparable or longer than the distance from the stamped phase mask to the bottom of the core region.
- Stamping of the phase mask directly on the device may simplify alignment of diffractive elements with ports or other device components especially when those components may be formed in the same or another stamping process.
- Many approaches to the creation of refractive index modulations or gratings are known in the art and may be employed in the fabrication of diffractive element sets.
- refractive index modulations or variations for forming diffractive elements will optimally fall in a range between about 10 ⁇ 4 and about 10 ⁇ 1 ; however, refractive index modulations or variations outside this range may be employed as well.
- Refractive index modulations or variations may be introduced by light of any wavelength (including ultraviolet light) that produces the desired refractive index changes, provided only that the photosensitive material employed is suitably stable in the presence of light in the desired operating wavelength range of the spectral filter. Exposure of a complete set of diffractive elements to substantially spatially uniform, refractive-index-changing light may be employed to tune the operative wavelength range of the diffractive element set.
- Exposure of the diffractive element set to spatially non-uniform refractive-index changing light may be employed to chirp or otherwise wavelength-modulate the spectral filter (described further hereinbelow).
- the sensitivity of planar waveguide materials to irradiation produced refractive index modulations may be increased using hydrogen-loading, flame-brushing, boron or other chemical doping, or other method known in the art, for example in the context of making fiber Bragg gratings.
- FIG. 1A A schematic overview of an exemplary planar waveguide spectral filter is shown in FIG. 1 .
- a cross section of a planar waveguide 100 shows diffractive elements 102 in cross section.
- the diffractive elements are formed at the interface between core 104 and cladding 106 , and comprise cladding material deposited into trenches etched to a depth d into the one surface of the waveguide core layer 104 .
- the diffractive elements 102 may instead be filled with a material other than the cladding material, provided the material has a refractive index differing from the core refractive index.
- An optical signal propagates in the x- and z-dimensions through the planar waveguide (substantially confined in the y-dimension by the planar waveguide) and is backscattered by the diffractive elements.
- n eff is the effective waveguide refractive index
- ⁇ is the physical spacing between diffractive contours (defined herein in terms of the differences in the lengths of ray paths s arc between input and output ports for successive diffractive elements, as shown in FIG.
- the effective waveguide index is not simply the refractive index n core of the bulk material comprising the core.
- the effective core index reflects rather the property of a particular mode supported by the planar waveguide and represents the vacuum speed of light divided by the phase velocity of the guided wave along the guiding direction of the waveguide.
- n core refractive index
- the effective core index reflects rather the property of a particular mode supported by the planar waveguide and represents the vacuum speed of light divided by the phase velocity of the guided wave along the guiding direction of the waveguide.
- there is a unique effective index for light traveling within the waveguide typically wavelength-dependent.
- transverse optical mode refers to optical modes having distinct electric field (E-field) amplitude variations along the direction locally normal to the plane of the planar waveguide. Each transverse optical mode actually comprises a family of modes having the same E-field variation along the local normal to the planar waveguide but having different propagation directions within the waveguide.
- the effective index for a particular optical mode is a function of the mode size and shape, the core index n core , the first and second cladding indices n 1 and n 2 , and the core thickness D (note these are not all independent of one another; the thickness and indices typically determine the mode size and shape).
- n 1 and n 2 The refractive indices of the two claddings, n 1 and n 2 , need not be the same.
- air, dielectric, metallic, or other suitable cladding material may be employed.
- Core and cladding materials should be chosen to provide acceptably low absorptive and scattering losses. Many appropriate silica, semiconductor, polymer, and other materials are known in the planar waveguide art and may be employed within the scope of the present disclosure and/or appended claims.
- each dashed curve represents a diffractive element 102 (equivalently, a diffractive element virtual contour).
- the diffractive elements are spatially defined by diffractive contours that are concentric circular arcs (with common center of curvature 110 ).
- Each diffractive element acts as a weak focusing mirror that images the input optical port 112 onto the output optical port 114 , with the ports located at conjugate image points defined by the circular diffractive element contours.
- each diffractive element may be defined by a unique virtual contour designed so as to convert the input optical signal wavefront into an output optical signal wavefront matched as well as possible for effective optical coupling into the output optical port.
- Simpler curvilinear diffractive element contours (such as circular arcs in this example) may be employed as approximations of fully optimized contours.
- Optical coupling may be optimized by designing the diffractive element set to reside within and fill at least a portion of the region of overlap between the designed input optical signal beam and the designed output optical signal beam. The design output beam may be visualized by injecting a signal backwards through the output port so as to impinge on the diffractive element set.
- the time-reverse of the backward injected signal is the design output beam.
- the design input signal beam corresponds to a beam launched toward the diffractive element set through the input port.
- the overlap region will be of large extent along a line bisecting the angle between input and output beams.
- the diffractive element set need not fill this entire length. Along this bisector direction, the diffractive element set need only be long enough to provide desired spectral resolution or overall reflective strength. In a single mode waveguide, the fully optimized focusing contour is unique as there is only one mode involved.
- FIG. 1C shows a particular ray path from the input optical port 112 to the output optical port 114 .
- the spacing between diffractive contours is arranged so that optical ray paths like the one shown in FIG. 1C increment by a constant amount from one diffractive contour to the next.
- optical path difference when referring herein to a multimode waveguide, phrases such as “optical path difference” and so forth must be defined in a meaningful and consistent fashion.
- One such definition may assume the effective index for the lowest-order incident and diffracted modes.
- Another suitable definition may assume an average effective index for all supported modes.
- Yet another definition may assume the bulk core index n core .
- Other suitable definitions may be used as well, and any suitable definition that reasonably approximates the modal indices, consistently applied, shall fall within the scope of the present disclosure and/or appended claims.)
- This constant optical ray path increment does not, however, necessarily result in uniform physical spacing between the diffractive element contours. In the exemplary embodiment of FIG. 1A-1C , diffractive contour spacings measured along the radial direction in FIGS.
- 1B and 1C are not constant, but instead are weakly chirped to yield a uniform increment in the optical ray path length. It is possible to vary the optical ray path increment to control the relative phase of signals diffracted by successive contours. Such control is useful for the introduction of various types of apodization.
- FIG. 2A a structure is shown wherein the diffractive elements 102 are located in the interior of the core 104 .
- Such interior-located diffractive elements may more strongly interact with lower order transverse modes.
- larger fractions of the transverse profiles of relevant transverse modes spanned by the diffractive elements, whether positioned at the core/cladding interface, within the core layer, and/or within the cladding layer, result in a correspondingly larger fraction of the input optical signal diffracted by the diffractive elements (for a given index contrast between the core and the diffractive elements). This in turn enables a desired level of optical power reflectivity by the diffractive element set using fewer diffractive elements.
- the diffractive elements 102 span the entire thickness of the core layer 104 . Diffractive elements spanning larger fractions of the transverse profiles of the relevant modes of the optical signal field would also tend to reduce variation in diffraction strength among the multiple transverse optical modes supported by the planar optical waveguide.
- FIG. 3 is shown the schematic geometry of light backscattering from diffractive elements within a multimode planar waveguide.
- the diffractive element geometry shown (located at the core/cladding interface) is simplified to facilitate definition of incidence angles for a representative input mode and a representative back-diffracted mode, but the following would apply to any diffractive element geometry.
- Each transverse optical mode within a multimode planar optical waveguide may be thought of as a superposition of two plane waves, each of which makes an angle ⁇ relative to the local plane of the waveguide (referred to as a propagation angle for the optical mode in question).
- Different transverse optical modes typically have different propagation angles ⁇ .
- the diffractive element set can back-diffract a specific input optical mode into the same counter-propagating optical mode or into one or more of the other counter-propagating optical modes of the planar waveguide.
- the relative strength of diffraction into the same or different transverse optical modes depends on the geometry of the diffractive elements and their placement relative to the core layer 104 .
- each successive optical mode “turns on” its characteristic incidence angle begins near the critical angle of the core-cladding interface and then decreases as the waveguide becomes thicker. As the mode number increases, the modes become relatively evenly spaced throughout the angular range from 0° to the critical angle. Diffraction may occur from an input optical signal in any supported optical mode to a back-diffracted output optical field in any supported optical mode. If there are N supported modes, there are N 2 potential scattering processes—some of which may be degenerate.
- the maximum back-diffracted wavelength occurs for the lowest-order optical mode diffracted back into the lowest-order optical mode.
- the minimum back-diffracted wavelength occurs for the highest-order support optical mode diffracted back into the highest-order supported optical mode.
- the interval between the maximum and minimum diffracted wavelengths, ⁇ can be approximated by
- the fractional bandpass of an exemplary multimode planar waveguide spectral filter with the core index 1.45 is shown as a function of cladding index.
- the fractional bandpass is approximately independent of the thickness of the waveguide core in the multiple transverse optical mode regime. It should be noted again that the waveguide need not necessarily have symmetric claddings.
- the fractional bandpass is essentially determined by the larger cladding index (i.e., the cladding index exhibiting the smaller index contrast with the core index). It may be desirable to have a relatively large refractive index differential when diffractive elements are formed from cladding material at a core-cladding interface, in order to increase diffraction strength or for other reasons.
- n clad not only affects the spectral filter bandwidth but also spatial mode matching to input/output optical signal fields.
- Minimal insertion losses will tend to occur when the respective angular spreads of the transverse modes supported by the planar optical waveguide and by input/output components (such as a multimode fiber, a multimode channel waveguide, an LED, a laser diode, and so forth) are substantially similar to one another.
- input/output components such as a multimode fiber, a multimode channel waveguide, an LED, a laser diode, and so forth
- One application for a multimode planar waveguide spectral filter is use as coarse WDM (wavelength division multiplexing) multiplexers and demultiplexers.
- bandpass widths of about 10 nm are typically employed.
- a minimal core-cladding index contrast of about 0.67 percent is required.
- Such an index contrast is readily achieved with many materials well known in the art.
- ⁇ is a wavelength range for the center wavelengths of individual mode-to-mode diffracted spectral peaks.
- a multimode planar waveguide spectral filter with constant optical path spacing among its diffractive elements will exhibit within this overall bandwidth ⁇ multiple discrete diffracted spectral peaks corresponding to the diffraction of the various forward optical modes into the various backward optical modes. If these mode-to-mode diffracted spectral peaks are narrower than ⁇ , then ⁇ is a good approximation of the overall bandwidth for the portion of the optical signal diffracted by the spectral filter (referred to as ⁇ filter ).
- the overall spectral width ⁇ filter is at least as broad as the broadest mode-to-mode diffracted spectral peak. If the diffractive element set has substantially constant optical path spacing along its operative optical path and the diffractive element set is on the 1-cm scale, these individual mode-to-mode diffracted spectral peaks will be on the order of 10 GHz wide (for a core refractive index of about 1.5 and if the diffractive element set is only weakly, i.e. less than about 70%, reflective). In the low reflective strength limit, the individual spectral peaks broaden in inverse proportion to the length of the diffractive element set.
- the overall length of the diffractive element set maybe reduced until adjacent diffracted spectral peaks overlap, or become comparable to or greater than the overall bandpass ⁇ .
- the individual mode-to-mode reflective bands would then substantially continuously span a spectral profile that encompasses the overall diffracted bandwidth given approximately by Eqs. 2 and 3. Shortening the diffractive element set will, however, also weaken the reflection strength of the diffractive element set and therefore increase insertion loss. Increasing the diffractive strength of individual diffractive elements may at least partly compensate for this.
- a multimode planar waveguide spectral filter having a reflection spectrum consisting of a series of adjacent diffracted peaks may provide useful functionality.
- a WDM system based on multiplexing spectral slices of light-emitting diode (LED) sources may be implemented and not depend critically on the detailed passband properties of the multiplexer/demultiplexer (mux/demux) employed.
- Such an LED spectral slicing WDM device may instead depend primarily on the central reflective channel wavelengths and channel widths (Eq. 3).
- Eq. 3 the central reflective channel wavelengths and channel widths
- Using matched mux and demux multimode spectral filters having the same reflective passband structure will tend to minimize net insertion loss.
- multi-mode planar waveguide devices are well suited to work with LED sources since the multimode planar waveguide readily accepts light in many transverse input optical modes and a continuum of in-plane optical modes.
- the discrete narrow diffracted spectral peaks characteristic of a fixed-optical-spacing multimode spectral filter may be shifted so that the diffractive element set provides a smooth continuous reflective profile throughout the fractional bandwidth given by Eq. 3.
- the diffractive element set may be formed so that the optical spacing between successive diffractive elements is chirped along the set.
- Local quantities ⁇ loc , ⁇ loc , and ⁇ loc characterizing localized portions of the diffractive element set, would be used in Equations (1), (2), and (3).
- the chirp may be sufficiently strong so that the mode-to-mode diffracted spectral peaks are shifted by an amount at least as large as the maximum local bandpass ⁇ loc for the diffractive element set.
- the overall diffractive spectral profile of the multimode spectral filter would be substantially continuous, and would be at least as spectrally broad as the larger of the broadest mode-to-mode peak or 2 ⁇ loc
- the optical spacing of the diffractive elements may be varied in many ways so as to provide a single smooth reflection spectrum for the diffractive element set.
- the diffractive element set could be divided into discrete segments, each having constant values of ⁇ loc , ⁇ loc , and ⁇ loc that differ from other segments of the set.
- the variations in ⁇ loc , ⁇ loc , and ⁇ loc may be achieved in a variety of ways.
- the physical spacing (i.e., ray path increment) of the diffractive elements may be spatially varied within a set (chirped, segmented, or otherwise). This may be achieved by suitable adaptation of the spatially selective fabrication of the diffractive element set, for example, by suitable modification of a lithographic mask or a stamping pattern.
- the effective modal indices may be spatially varied within a set of diffractive elements, thereby altering ⁇ loc , ⁇ loc , and ⁇ loc for a fixed physical spacing of the diffractive elements. This may be accomplished in a variety of ways, for example, by spatially varying exposure of sensitive waveguide material to ultraviolet radiation.
- individual diffractive element sets may be overlapped, interleaved, overlaid, and/or positioned sequentially in/on the planar waveguide.
- polychromatic light enters a single input optical port.
- Multiple overlapped, interleaved, overlaid, or sequential diffractive element sets are employed, each of which has a diffractive element optical spacing (constant or otherwise) set to be reflective within one (or more) spectral channels, and each of which routes reflected light from the input optical port to one of multiple output optical ports.
- the multiple diffractive element sets collectively route light from the input optical port to the multiple output optical ports with a predetermined mapping of input spectral channels to output optical ports—each diffractive element set handles the mapping of one or more spectral channels to a specific output optical port.
- a multiplexer operates in a reverse manner from the demultiplexer.
- each diffractive element contour may be optimized to image the input port onto the output port in a phase coherent manner.
- Inputs to the design are the detailed structure of the optical input and output ports and their locations.
- Standard ray tracing approaches to optical element design may provide a diffractive contour at each optical distance into the planar waveguide that will provide an optimal imaging of the input signal at the input port onto the optimal output signal at the output port.
- Simple curves may be employed as approximations of the fully optimized contours.
- Diffractive contours are spaced by an optical path difference (as described above) that provides for the field image of successive diffractive contours to be substantially in phase at a desired wavelength. If the overall response of the diffractive element set is to be apodized with phase modulation, the optical spacing of successive diffractive element contours may be controlled to provide required phase differences between diffracted components at the output port.
- An alternative approach to designing the diffractive element contours for a diffractive element set is to calculate interference patterns between simulated fields at a desired wavelength entering the input port and exiting the output port in specific planar waveguide optical transverse modes.
- One approach is to consider the interference pattern of each input mode having a desired optical field variation in the plane of the slab waveguide and calculating the interference pattern with a field coupled by the diffractive element set to a desired output optical field variation in the plane of the slab at the output port.
- the net pattern to be formed or written as a set of diffractive elements would be the sum of the individual calculated mode-to-mode interference patterns.
- suitable discretization is applied as needed for any lithographic or UV exposure approach that is utilized for fabrication. It is also possible to form or write the diffractive element set based on a single input-mode-to-output-mode interference pattern to preferentially couple certain modes through the planar waveguide.
- the core consists of a material of appropriate index that is also photosensitive at the wavelength of the desired operational signal beams.
- the input and output recording beams (same wavelength as operational signal beams of the envisioned device) are overlapped in the core and the interference pattern between them is recorded.
- the core material is developed and, if necessary, a cladding may be deposited or attached by other means.
- the holographic structure may also be designed by interference of computer-generated beams. Unlike in single mode waveguides, the resulting interference pattern extends in all three spatial dimensions. Reduction to a planar slab waveguide may occur by slicing through an appropriate horizontal cross section of the interference pattern. Alternatively, the three dimensional hologram can be built up and approximated by combining several of the discrete cross-sections and then stacking them up. This may be implemented in several lithographic steps.
Abstract
Description
- This application is a continuation of U.S. non-provisional application Ser. No. 12/367,159, which in turn is a continuation of U.S. non-provisional application Ser. No. 11/334,039 filed Jan. 17, 2006, which in turn is a continuation of U.S. non-provisional application Ser. No. 10/842,790 filed May 11, 2004 (now U.S. Pat. No. 6,987,911), which in turn claims benefit of U.S. provisional App. No. 60/486,451 filed Jul. 10, 2003, said provisional and non-provisional applications being hereby incorporated by reference as if fully set forth herein.
- Said U.S. application Ser. No. 10/842,790 is a continuation-in-part of U.S. non-provisional application Ser. No. 10/653,876 filed Sep. 2, 2003 (now U.S. Pat. No. 6,829,417), which is in turn a continuation-in-part of U.S. non-provisional application Ser. No. 10/229,444 filed Aug. 27, 2002 (now U.S. Pat. No. 6,678,429). Said application Ser. No. 10/229,444 in turn claims benefit of U.S. provisional App. No. 60/315,302 filed Aug. 27, 2001 and U.S. provisional App. No. 60/370,182 filed Apr. 4, 2002. Said application Ser. No. 10/653,876 in turn claims benefit of U.S. provisional App. No. 60/468,479 filed May 7, 2003 and U.S. provisional App. No. 60/486,450 filed Jul. 10, 2003. Each of said provisional and non-provisional applications is hereby incorporated by reference as if fully set forth herein.
- Said U.S. application Ser. No. 10/842,790 is a continuation-in-part of U.S. non-provisional application Ser. No. 09/811,081 filed Mar. 16, 2001 (now U.S. Pat. No. 6,879,441), and a continuation-in-part of U.S. non-provisional application Ser. No. 09/843,597 filed Apr. 26, 2001 (now U.S. Pat. No. 6,965,464) which is in turn a continuation-in-part of said application Ser. No. 09/811,081. Said application Ser. No. 09/811,081 in turn claims benefit of U.S. provisional App. No. 60/190,126 filed Mar. 16, 2000, U.S. provisional App. No. 60/199,790 filed Apr. 26, 2000, U.S. provisional App. No. 60/235,330 filed Sep. 26, 2000, and U.S. provisional App. No. 60/247,231 filed Nov. 10, 2000. Each of said provisional and non-provisional applications is hereby incorporated by reference as if fully set forth herein.
- The field of the present invention relates to optical devices incorporating distributed optical structures. In particular, multimode planar waveguide spectral filters are disclosed herein.
- A spectral filter comprises a planar optical waveguide having at least one set of diffractive elements. The planar optical waveguide substantially confines in one transverse spatial dimension an optical signal propagating in two other spatial dimensions therein. The planar waveguide supports multiple optical transverse modes in the confined transverse dimension. Each diffractive element set routes, between a corresponding input optical port and a corresponding output optical port, a corresponding diffracted portion of the optical signal propagating in the planar waveguide that is diffracted by the diffractive element set. The corresponding diffracted portion of the optical signal reaches the corresponding output optical port as a superposition of multiple optical transverse modes supported by the planar optical waveguide. A corresponding multimode optical source may be positioned and aligned so as to launch the optical signal into the planar waveguide, through the corresponding input optical port, as a superposition of multiple optical transverse modes supported by the planar optical waveguide. A corresponding multimode output waveguide may be positioned and aligned so as to receive, through the corresponding output optical port, the corresponding diffracted portion of the optical signal. Multiple diffractive element sets may route corresponding diffracted portions of optical signal between one or more corresponding input optical ports and one or more corresponding output optical ports.
- Objects and advantages pertaining to multimode planar waveguide spectral filters may become apparent upon referring to the disclosed embodiments as illustrated in the drawings and disclosed in the following written description and/or claims
-
FIGS. 1A and 1B are side and top schematic views, respectively, of a planar waveguide spectral filter.FIG. 1C is a schematic top view showing an optical path between input and output optical ports of a planar waveguide spectral filter. -
FIGS. 2A and 2B are side schematic views of planar waveguide spectral filters. -
FIG. 3 is a side schematic view of a planar waveguide spectral filter. -
FIG. 4 illustrates the dependence of mode angle on planar waveguide thickness parameter. -
FIG. 5 illustrates the dependence of fractional bandpass on cladding index for a planar waveguide spectral filter. - The embodiments shown in the Figures are exemplary, and should not be construed as limiting the scope of the present disclosure and/or appended claims.
- A spectral filter according to the present disclosure comprises a multimode planar optical waveguide having at least one set of diffractive elements. The planar optical waveguide substantially confines in one transverse dimension optical signals propagating in the other two spatial dimensions. The planar waveguide supports multiple transverse optical modes in the confined transverse dimension. An optical signal propagates through the multimode planar optical waveguide as a superposition of the supported optical modes. However, the relative phases of the modes of such a superposition generally vary with propagation distance through the waveguide, since the optical modes propagate at differing phase velocities (i.e., the waveguide exhibits modal dispersion). The planar waveguide typically comprises a core (a two-dimensional sheet or layer) surrounded by lower-index cladding. The core is fabricated using one or more dielectric materials substantially transparent over a desired operating wavelength range. In some instances one or both claddings may be vacuum, air, or other ambient atmosphere. More typically, one or both claddings comprise layers of dielectric material(s), with the cladding refractive indices n1 and n2 typically being smaller than the core refractive index ncore. (In some instances in which short optical paths are employed and some degree of optical loss can be tolerated, the cladding indices might be larger than the core index while still enabling the planar waveguide to support guided, albeit lossy, optical modes.) The planar waveguide may be secured to a substrate, for facilitating manufacture, for mechanical support, and/or for other reasons.
- The set of diffractive elements of the spectral filter may also be referred to as: a set of holographic elements; a volume hologram; a distributed reflective element, distributed reflector, or distributed Bragg reflector (DBR); a Bragg reflective grating (BRG); a holographic Bragg reflector (HBR); a directional photonic-bandgap structure; a mode-selective photonic crystal; or other equivalent terms of art. Each diffractive element of the set diffracts, reflects, scatters, or otherwise redirects a portion of an incident optical signal (said process hereinafter simply referred to as diffraction). Each diffractive element of the set typically comprises some suitable alteration of the planar waveguide (ridge, groove, index modulation, density modulation, and so on), and is spatially defined by a virtual two-dimensional curvilinear diffractive element contour, the curvilinear shape of the contour typically being configured to impart desired spatial characteristics onto the diffracted portion of the optical signal. The curvilinear diffractive elements of the set (or equivalently, their corresponding contours) are spatially arranged with respect to one another so that the corresponding portions of the optical signal diffracted by each element interfere with one another, so as to impart desired spectral and/or temporal characteristics onto the portion of the optical signal collectively diffracted from the set of diffractive elements. The diffractive elements in the set are arranged so that an input optical signal, entering the planar waveguide through an input optical port, is successively incident on diffractive elements of the set. A fraction of the incident amplitude is diffracted by a diffractive element and the remainder transmitted and incident on another diffractive element, and so on successively through the set of diffractive elements. The diffractive elements are therefore spaced substantially longitudinally along the propagation direction of the incident optical signal (in contrast to a traditional surface grating, in which the diffractive elements, i.e. grating lines, are spaced transversely across the wavefront of a normally incident optical signal). Each curvilinear diffractive element is shaped to direct its diffracted portion of the optical signal to an output optical port, typically propagating back through earlier diffractive elements of the set. The relative spatial arrangement (i.e. longitudinal spacing) of the diffractive elements of the set yields desired spectral and/or temporal characteristics for the overall diffracted optical signal reaching the output optical port. It should be noted that optical ports (input and/or output) may be defined structurally (for example, by an aperture, waveguide, fiber, lens, or other optical component) and/or functionally (i.e., by a spatial location, convergence/divergence/collimation, and/or propagation direction). For a single-mode planar waveguide, such a set of diffractive elements may be arranged to yield an arbitrary spectral transfer function (in terms of amplitude and phase). In a multimode planar waveguide, the subject of the present disclosure, modal dispersion and mode-to-mode coupling of diffracted portions of the optical signal limit the range of spectral transfer functions that may be implemented.
- The set of diffractive elements of the spectral filter provides dual functionality, spatially routing an optical signal between an input optical port and an output optical port, while at the same time acting as a spectral filter. The curvilinear diffractive elements may be designed (by computer generation, for example) so as to provide optimal routing, imaging, or focusing of the optical signal between an input optical port and a desired output optical port, thus reducing or minimizing insertion loss of the spectral filter. Simple curvilinear diffractive elements (segments of circles, ellipses, parabolas, hyperbolas, and so forth), if not optimal, may be employed as approximations of fully optimized contours. A wide range of fabrication techniques may be employed for forming the diffractive element set, and any suitable technique(s) may be employed while remaining within the scope of the present disclosure and/or appended claims. The following are exemplary only, and are not intended to be exhaustive.
- Diffractive elements may be formed lithographically on the surface of a multimode planar optical waveguide, or at one or both interfaces between core and cladding of a multimode planar optical waveguide. Diffractive contours may be formed lithographically in the interior of the core layer and/or a cladding layer of the planar optical waveguide using one or more spatial lithography steps performed after an initial partial deposition of layer material. Diffractive elements may be formed in the core and/or cladding layers by projecting ultraviolet light or other suitable radiation through an amplitude and/or phase mask so as to create an interference pattern within the multimode planar waveguide (fabricated at least in part with suitably sensitive material) whose fringe contours match the desired diffractive element contours. Alteration of the refractive index by exposure to ultraviolet or other radiation results in index-modulated diffractive elements. The mask may be zeroth-order-suppressed according to methods known in the art, including the arts associated with fabrication of fiber Bragg gratings. The amplitude and/or phase mask may be produced lithographically via laser writer or e-beam, it may be interferometrically formed, or it may be formed by any other suitable technique. In instances where resolution is insufficient to produce a mask having required feature sizes, a larger scale mask may be produced and reduced to needed dimensions via photoreduction lithography, as in a stepper, to produce a mask at the needed scale. Diffractive elements may be formed by molding, stamping, impressing, embossing, or other mechanical processes. A phase mask may be stamped onto the core or cladding surface followed by optical exposure to create diffractive elements throughout the core and or cladding region. The optical or UV source used to write the diffractive elements in this case should have a coherence length comparable or longer than the distance from the stamped phase mask to the bottom of the core region. Stamping of the phase mask directly on the device may simplify alignment of diffractive elements with ports or other device components especially when those components may be formed in the same or another stamping process. Many approaches to the creation of refractive index modulations or gratings are known in the art and may be employed in the fabrication of diffractive element sets.
- Irradiation-produced refractive index modulations or variations for forming diffractive elements will optimally fall in a range between about 10−4 and about 10−1; however, refractive index modulations or variations outside this range may be employed as well. Refractive index modulations or variations may be introduced by light of any wavelength (including ultraviolet light) that produces the desired refractive index changes, provided only that the photosensitive material employed is suitably stable in the presence of light in the desired operating wavelength range of the spectral filter. Exposure of a complete set of diffractive elements to substantially spatially uniform, refractive-index-changing light may be employed to tune the operative wavelength range of the diffractive element set. Exposure of the diffractive element set to spatially non-uniform refractive-index changing light may be employed to chirp or otherwise wavelength-modulate the spectral filter (described further hereinbelow). The sensitivity of planar waveguide materials to irradiation produced refractive index modulations may be increased using hydrogen-loading, flame-brushing, boron or other chemical doping, or other method known in the art, for example in the context of making fiber Bragg gratings.
- A schematic overview of an exemplary planar waveguide spectral filter is shown in
FIG. 1 . InFIG. 1A , a cross section of a planar waveguide 100 (withcore 104 and first andsecond claddings 106 and 108) showsdiffractive elements 102 in cross section. In this exemplary embodiment, the diffractive elements are formed at the interface betweencore 104 andcladding 106, and comprise cladding material deposited into trenches etched to a depth d into the one surface of thewaveguide core layer 104. Thediffractive elements 102 may instead be filled with a material other than the cladding material, provided the material has a refractive index differing from the core refractive index. An optical signal propagates in the x- and z-dimensions through the planar waveguide (substantially confined in the y-dimension by the planar waveguide) and is backscattered by the diffractive elements. Light whose vacuum wavelength λvac=2neff Λ will be most strongly backscattered (due to constructive interference among the portions of the incident optical signal diffracted by the individual diffractive elements). Here neff is the effective waveguide refractive index and Λ is the physical spacing between diffractive contours (defined herein in terms of the differences in the lengths of ray paths sarc between input and output ports for successive diffractive elements, as shown inFIG. 1C ; the spacing may be averaged over a diffractive element if the ray pathlength is not constant across the diffractive element, i.e., if the diffractive element curvilinear contour is not fully spatially optimized). For example, if λvac=1.5 μm is to be reflected and the effective core refractive index for the mode of interest is 1.45, the one-way ray path spacing between diffractive elements should be about 0.517 μm. - It should be noted that the effective waveguide index is not simply the refractive index ncore of the bulk material comprising the core. The effective core index reflects rather the property of a particular mode supported by the planar waveguide and represents the vacuum speed of light divided by the phase velocity of the guided wave along the guiding direction of the waveguide. In a single-mode waveguide, there is a unique effective index for light traveling within the waveguide (typically wavelength-dependent). For a multimode waveguide, the subject of the present disclosure, there is a range of effective waveguide refractive indices—one for each of the transverse optical modes that is supported by the waveguide. In the context of planar waveguides, “transverse optical mode” refers to optical modes having distinct electric field (E-field) amplitude variations along the direction locally normal to the plane of the planar waveguide. Each transverse optical mode actually comprises a family of modes having the same E-field variation along the local normal to the planar waveguide but having different propagation directions within the waveguide. The effective index for a particular optical mode is a function of the mode size and shape, the core index ncore, the first and second cladding indices n1 and n2, and the core thickness D (note these are not all independent of one another; the thickness and indices typically determine the mode size and shape). The refractive indices of the two claddings, n1 and n2, need not be the same. The cladding index closer to the core index (i.e., the greater of n1 and n2) shall be denoted hereinafter as nclad. Note that air, dielectric, metallic, or other suitable cladding material may be employed. Core and cladding materials should be chosen to provide acceptably low absorptive and scattering losses. Many appropriate silica, semiconductor, polymer, and other materials are known in the planar waveguide art and may be employed within the scope of the present disclosure and/or appended claims.
- In
FIG. 1B , a top view of the diffractive element set is shown. Each dashed curve represents a diffractive element 102 (equivalently, a diffractive element virtual contour). In this example the diffractive elements are spatially defined by diffractive contours that are concentric circular arcs (with common center of curvature 110). Each diffractive element acts as a weak focusing mirror that images the inputoptical port 112 onto the outputoptical port 114, with the ports located at conjugate image points defined by the circular diffractive element contours. In a fully spatially optimized device, each diffractive element may be defined by a unique virtual contour designed so as to convert the input optical signal wavefront into an output optical signal wavefront matched as well as possible for effective optical coupling into the output optical port. Simpler curvilinear diffractive element contours (such as circular arcs in this example) may be employed as approximations of fully optimized contours. Optical coupling may be optimized by designing the diffractive element set to reside within and fill at least a portion of the region of overlap between the designed input optical signal beam and the designed output optical signal beam. The design output beam may be visualized by injecting a signal backwards through the output port so as to impinge on the diffractive element set. The time-reverse of the backward injected signal is the design output beam. The design input signal beam corresponds to a beam launched toward the diffractive element set through the input port. When the input and output ports are in close proximity and the design input and output beams are nearly anti-parallel, the overlap region will be of large extent along a line bisecting the angle between input and output beams. The diffractive element set need not fill this entire length. Along this bisector direction, the diffractive element set need only be long enough to provide desired spectral resolution or overall reflective strength. In a single mode waveguide, the fully optimized focusing contour is unique as there is only one mode involved. In a multimode waveguide (the subject of the present disclosure), coupling by the diffractive element set of all possible input modes to all of the possible output modes is relevant.FIG. 1C shows a particular ray path from the inputoptical port 112 to the outputoptical port 114. Typically, the spacing between diffractive contours is arranged so that optical ray paths like the one shown inFIG. 1C increment by a constant amount from one diffractive contour to the next. (As an aside, since for a specific optical mode the optical pathlength difference between diffractive elements depends on the relevant modal indices as well as the ray pathlength difference between the diffractive elements, and since the modal indices vary among the supported transverse modes, the optical path increment cannot be defined uniquely in a multimode waveguide. Therefore, when referring herein to a multimode waveguide, phrases such as “optical path difference” and so forth must be defined in a meaningful and consistent fashion. One such definition may assume the effective index for the lowest-order incident and diffracted modes. Another suitable definition may assume an average effective index for all supported modes. Yet another definition may assume the bulk core index ncore. Other suitable definitions may be used as well, and any suitable definition that reasonably approximates the modal indices, consistently applied, shall fall within the scope of the present disclosure and/or appended claims.) This constant optical ray path increment does not, however, necessarily result in uniform physical spacing between the diffractive element contours. In the exemplary embodiment ofFIG. 1A-1C , diffractive contour spacings measured along the radial direction inFIGS. 1B and 1C are not constant, but instead are weakly chirped to yield a uniform increment in the optical ray path length. It is possible to vary the optical ray path increment to control the relative phase of signals diffracted by successive contours. Such control is useful for the introduction of various types of apodization. - In
FIG. 2A , a structure is shown wherein thediffractive elements 102 are located in the interior of thecore 104. Such interior-located diffractive elements may more strongly interact with lower order transverse modes. In general, larger fractions of the transverse profiles of relevant transverse modes spanned by the diffractive elements, whether positioned at the core/cladding interface, within the core layer, and/or within the cladding layer, result in a correspondingly larger fraction of the input optical signal diffracted by the diffractive elements (for a given index contrast between the core and the diffractive elements). This in turn enables a desired level of optical power reflectivity by the diffractive element set using fewer diffractive elements. InFIG. 2B , thediffractive elements 102 span the entire thickness of thecore layer 104. Diffractive elements spanning larger fractions of the transverse profiles of the relevant modes of the optical signal field would also tend to reduce variation in diffraction strength among the multiple transverse optical modes supported by the planar optical waveguide. - In
FIG. 3 is shown the schematic geometry of light backscattering from diffractive elements within a multimode planar waveguide. The diffractive element geometry shown (located at the core/cladding interface) is simplified to facilitate definition of incidence angles for a representative input mode and a representative back-diffracted mode, but the following would apply to any diffractive element geometry. Each transverse optical mode within a multimode planar optical waveguide may be thought of as a superposition of two plane waves, each of which makes an angle θ relative to the local plane of the waveguide (referred to as a propagation angle for the optical mode in question). Different transverse optical modes typically have different propagation angles θ. The propagation angles θin and θout shown inFIG. 3 represent, respectively, the angles made by the constituent plane wave subcomponents of input and back diffracted optical modes of the waveguide. Note that the input angle, θin, and the back-diffracted output angle, θout, are not shown as being equal. In general, the diffractive element set can back-diffract a specific input optical mode into the same counter-propagating optical mode or into one or more of the other counter-propagating optical modes of the planar waveguide. The relative strength of diffraction into the same or different transverse optical modes depends on the geometry of the diffractive elements and their placement relative to thecore layer 104. - Each input-mode-to-output-mode diffraction process will occur most strongly at a unique vacuum wavelength. Diffraction will occur strongly at wavelengths satisfying the following equation
-
λ/n core=Λ(cos θin+cos θout)/m (1) - where m=1, 2, 3, . . . is the diffractive order. The angles in Eq. 1 are, as described above, the characteristic modal propagation angles for the incident and diffracted optical modes, respectively. In
FIG. 4 , we plot the characteristic modal propagation angles for all modes that exist in a planar guide as a function of the effective guide thickness ncore d/λ, where d is the physical waveguide thickness as shown inFIG. 1 . To calculateFIG. 4 , a core index ncore=1.45 and a cladding index nclad=1.43 are assumed. As one moves to the right inFIG. 4 , the waveguide core is getting thicker. Additional optical modes are supported as the core thickness increases. As each successive optical mode “turns on”, its characteristic incidence angle begins near the critical angle of the core-cladding interface and then decreases as the waveguide becomes thicker. As the mode number increases, the modes become relatively evenly spaced throughout the angular range from 0° to the critical angle. Diffraction may occur from an input optical signal in any supported optical mode to a back-diffracted output optical field in any supported optical mode. If there are N supported modes, there are N2 potential scattering processes—some of which may be degenerate. - The maximum back-diffracted wavelength occurs for the lowest-order optical mode diffracted back into the lowest-order optical mode. The minimum back-diffracted wavelength occurs for the highest-order support optical mode diffracted back into the highest-order supported optical mode. The interval between the maximum and minimum diffracted wavelengths, Δλ, can be approximated by
-
Δλ=2Λn core(1−cos θH)/m (2) - where we have approximated the propagation angle of the lowest-order optical mode to be 0° and the propagation angle of the highest-order supported optical mode to be θH=π/2−sin−1(nclad/ncore). In many cases of interest, the diffracted bandpass width, Δλ, is quite small relative to the diffracted vacuum wavelength λ. In such cases, we can approximate the diffracted vacuum wavelength as λ=2ncoreλ/m and calculate a fractional filter bandpass ratio
-
Δλ/λ=(n core −n clad)/n core (3) - where we have inserted the definition of θH into Eq. 2 to yield Eq. 3. The fractional bandpass for the portion of the optical signal diffracted by the diffractive element set of the multimode spectral filter is found to be simply related, via Eq. 3, to the refractive index difference between the core and cladding. A more accurate value of Δλ/λ for specific waveguide parameters can be calculated by standard methods well known in the art, but for many design purposes, Eq. 3 suffices.
- In
FIG. 5 , the fractional bandpass of an exemplary multimode planar waveguide spectral filter with the core index 1.45 is shown as a function of cladding index. The fractional bandpass is approximately independent of the thickness of the waveguide core in the multiple transverse optical mode regime. It should be noted again that the waveguide need not necessarily have symmetric claddings. The fractional bandpass is essentially determined by the larger cladding index (i.e., the cladding index exhibiting the smaller index contrast with the core index). It may be desirable to have a relatively large refractive index differential when diffractive elements are formed from cladding material at a core-cladding interface, in order to increase diffraction strength or for other reasons. As long as one of the core-cladding interfaces has a sufficiently low refractive index contrast, the range of guided modes will remain small and Eq. 3 will typically suffice. An important design consideration for a multimode planar waveguide spectral filter is the degree to which the supported planar waveguide optical modes match the modes of input and output optical signal fields, for example optical modes supported by multimode optical fiber. The value of nclad not only affects the spectral filter bandwidth but also spatial mode matching to input/output optical signal fields. Minimal insertion losses will tend to occur when the respective angular spreads of the transverse modes supported by the planar optical waveguide and by input/output components (such as a multimode fiber, a multimode channel waveguide, an LED, a laser diode, and so forth) are substantially similar to one another. - One application for a multimode planar waveguide spectral filter is use as coarse WDM (wavelength division multiplexing) multiplexers and demultiplexers. In that application area, bandpass widths of about 10 nm are typically employed. With a 10-nm bandpass width and an operating wavelength of 1.5 microns, a minimal core-cladding index contrast of about 0.67 percent is required. Such an index contrast is readily achieved with many materials well known in the art.
- It should be noted that Δλ as given by Eqs. (2) and (3) is a wavelength range for the center wavelengths of individual mode-to-mode diffracted spectral peaks. A multimode planar waveguide spectral filter with constant optical path spacing among its diffractive elements will exhibit within this overall bandwidth Δλ multiple discrete diffracted spectral peaks corresponding to the diffraction of the various forward optical modes into the various backward optical modes. If these mode-to-mode diffracted spectral peaks are narrower than Δλ, then Δλ is a good approximation of the overall bandwidth for the portion of the optical signal diffracted by the spectral filter (referred to as Δλfilter). If, on the other hand, the mode-to-mode diffracted spectral peaks are broader than Δλ, then the overall spectral width Δλfilter is at least as broad as the broadest mode-to-mode diffracted spectral peak. If the diffractive element set has substantially constant optical path spacing along its operative optical path and the diffractive element set is on the 1-cm scale, these individual mode-to-mode diffracted spectral peaks will be on the order of 10 GHz wide (for a core refractive index of about 1.5 and if the diffractive element set is only weakly, i.e. less than about 70%, reflective). In the low reflective strength limit, the individual spectral peaks broaden in inverse proportion to the length of the diffractive element set. The overall length of the diffractive element set maybe reduced until adjacent diffracted spectral peaks overlap, or become comparable to or greater than the overall bandpass Δλ. The individual mode-to-mode reflective bands would then substantially continuously span a spectral profile that encompasses the overall diffracted bandwidth given approximately by Eqs. 2 and 3. Shortening the diffractive element set will, however, also weaken the reflection strength of the diffractive element set and therefore increase insertion loss. Increasing the diffractive strength of individual diffractive elements may at least partly compensate for this.
- In some cases, a multimode planar waveguide spectral filter having a reflection spectrum consisting of a series of adjacent diffracted peaks may provide useful functionality. For example, a WDM system based on multiplexing spectral slices of light-emitting diode (LED) sources may be implemented and not depend critically on the detailed passband properties of the multiplexer/demultiplexer (mux/demux) employed. Such an LED spectral slicing WDM device may instead depend primarily on the central reflective channel wavelengths and channel widths (Eq. 3). Using matched mux and demux multimode spectral filters having the same reflective passband structure will tend to minimize net insertion loss. It should be noted that multi-mode planar waveguide devices are well suited to work with LED sources since the multimode planar waveguide readily accepts light in many transverse input optical modes and a continuum of in-plane optical modes.
- The discrete narrow diffracted spectral peaks characteristic of a fixed-optical-spacing multimode spectral filter may be shifted so that the diffractive element set provides a smooth continuous reflective profile throughout the fractional bandwidth given by Eq. 3. For example, the diffractive element set may be formed so that the optical spacing between successive diffractive elements is chirped along the set. Local quantities Λloc, Δλloc, and λloc, characterizing localized portions of the diffractive element set, would be used in Equations (1), (2), and (3). The chirp may be sufficiently strong so that the mode-to-mode diffracted spectral peaks are shifted by an amount at least as large as the maximum local bandpass Δλloc for the diffractive element set. As a result, the overall diffractive spectral profile of the multimode spectral filter would be substantially continuous, and would be at least as spectrally broad as the larger of the broadest mode-to-mode peak or 2Δλloc Instead of a monotonic variation of Λloc, Δλloc, and λloc along the diffractive element set (i.e., chirp), the optical spacing of the diffractive elements may be varied in many ways so as to provide a single smooth reflection spectrum for the diffractive element set. For example, the diffractive element set could be divided into discrete segments, each having constant values of Λloc, Δλloc, and λloc that differ from other segments of the set. The variations in Λloc, Δλloc, and λloc may be achieved in a variety of ways. The physical spacing (i.e., ray path increment) of the diffractive elements may be spatially varied within a set (chirped, segmented, or otherwise). This may be achieved by suitable adaptation of the spatially selective fabrication of the diffractive element set, for example, by suitable modification of a lithographic mask or a stamping pattern. Alternatively, the effective modal indices may be spatially varied within a set of diffractive elements, thereby altering Λloc, Δλloc, and λloc for a fixed physical spacing of the diffractive elements. This may be accomplished in a variety of ways, for example, by spatially varying exposure of sensitive waveguide material to ultraviolet radiation.
- In order to make a multiplexer or demultiplexer using sets of diffractive elements, individual diffractive element sets may be overlapped, interleaved, overlaid, and/or positioned sequentially in/on the planar waveguide. For a demux, polychromatic light enters a single input optical port. Multiple overlapped, interleaved, overlaid, or sequential diffractive element sets are employed, each of which has a diffractive element optical spacing (constant or otherwise) set to be reflective within one (or more) spectral channels, and each of which routes reflected light from the input optical port to one of multiple output optical ports. The multiple diffractive element sets collectively route light from the input optical port to the multiple output optical ports with a predetermined mapping of input spectral channels to output optical ports—each diffractive element set handles the mapping of one or more spectral channels to a specific output optical port. A multiplexer operates in a reverse manner from the demultiplexer.
- The curvilinear shape of the diffractive element contours may be determined by a variety of standard optical imaging system design tools. Essentially, each diffractive element contour may be optimized to image the input port onto the output port in a phase coherent manner. Inputs to the design are the detailed structure of the optical input and output ports and their locations. Standard ray tracing approaches to optical element design may provide a diffractive contour at each optical distance into the planar waveguide that will provide an optimal imaging of the input signal at the input port onto the optimal output signal at the output port. Simple curves may be employed as approximations of the fully optimized contours. Diffractive contours are spaced by an optical path difference (as described above) that provides for the field image of successive diffractive contours to be substantially in phase at a desired wavelength. If the overall response of the diffractive element set is to be apodized with phase modulation, the optical spacing of successive diffractive element contours may be controlled to provide required phase differences between diffracted components at the output port.
- An alternative approach to designing the diffractive element contours for a diffractive element set is to calculate interference patterns between simulated fields at a desired wavelength entering the input port and exiting the output port in specific planar waveguide optical transverse modes. One approach is to consider the interference pattern of each input mode having a desired optical field variation in the plane of the slab waveguide and calculating the interference pattern with a field coupled by the diffractive element set to a desired output optical field variation in the plane of the slab at the output port. The net pattern to be formed or written as a set of diffractive elements would be the sum of the individual calculated mode-to-mode interference patterns. In forming or writing a summed pattern for the diffractive element set, suitable discretization is applied as needed for any lithographic or UV exposure approach that is utilized for fabrication. It is also possible to form or write the diffractive element set based on a single input-mode-to-output-mode interference pattern to preferentially couple certain modes through the planar waveguide.
- In an alternative method for making the diffractive element structure, the core consists of a material of appropriate index that is also photosensitive at the wavelength of the desired operational signal beams. As in traditional holography, the input and output recording beams (same wavelength as operational signal beams of the envisioned device) are overlapped in the core and the interference pattern between them is recorded. Subsequently the core material is developed and, if necessary, a cladding may be deposited or attached by other means.
- The holographic structure may also be designed by interference of computer-generated beams. Unlike in single mode waveguides, the resulting interference pattern extends in all three spatial dimensions. Reduction to a planar slab waveguide may occur by slicing through an appropriate horizontal cross section of the interference pattern. Alternatively, the three dimensional hologram can be built up and approximated by combining several of the discrete cross-sections and then stacking them up. This may be implemented in several lithographic steps.
- It should be noted that many of the embodiments depicted in this disclosure are only shown schematically, and that not all the features may be shown in full detail or in proper proportion and/or location. Certain features or structures may be exaggerated relative to others for clarity. In particular, it should be noted that the numbers of diffractive elements in an actual device may typically be larger than that shown in the Figures. The numbers of diffractive elements is reduced in the Figures for clarity. It should be further noted that the embodiments shown in the Figures are exemplary only, and should not be construed as specifically limiting the scope of the written description or the claims set forth herein. It is intended that equivalents of the disclosed exemplary embodiments and methods shall fall within the scope of the present disclosure. It is intended that the disclosed exemplary embodiments and methods, and equivalents thereof, may be modified while remaining within the scope of the present disclosure.
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20130265624A1 (en) * | 2012-04-05 | 2013-10-10 | Oracle International Corporation | Surface-normal optical coupling using a holographic recording material |
Families Citing this family (102)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7194164B2 (en) | 2000-03-16 | 2007-03-20 | Lightsmyth Technologies Inc | Distributed optical structures with improved diffraction efficiency and/or improved optical coupling |
US7519248B2 (en) | 2000-03-16 | 2009-04-14 | Lightsmyth Technologies Inc | Transmission gratings designed by computed interference between simulated optical signals and fabricated by reduction lithography |
US6879441B1 (en) * | 2000-03-16 | 2005-04-12 | Thomas Mossberg | Holographic spectral filter |
USRE41570E1 (en) | 2000-03-16 | 2010-08-24 | Greiner Christoph M | Distributed optical structures in a planar waveguide coupling in-plane and out-of-plane optical signals |
USRE42206E1 (en) | 2000-03-16 | 2011-03-08 | Steyphi Services De Llc | Multiple wavelength optical source |
US7773842B2 (en) * | 2001-08-27 | 2010-08-10 | Greiner Christoph M | Amplitude and phase control in distributed optical structures |
USRE42407E1 (en) | 2000-03-16 | 2011-05-31 | Steyphi Services De Llc | Distributed optical structures with improved diffraction efficiency and/or improved optical coupling |
US6987911B2 (en) * | 2000-03-16 | 2006-01-17 | Lightsmyth Technologies, Inc. | Multimode planar waveguide spectral filter |
WO2004057376A2 (en) | 2002-12-17 | 2004-07-08 | Lightsmyth Technologies Incorporated | Optical multiplexing device |
US7260290B1 (en) | 2003-12-24 | 2007-08-21 | Lightsmyth Technologies Inc | Distributed optical structures exhibiting reduced optical loss |
US7181103B1 (en) | 2004-02-20 | 2007-02-20 | Lightsmyth Technologies Inc | Optical interconnect structures incorporating sets of diffractive elements |
US7190858B1 (en) | 2004-06-16 | 2007-03-13 | Lightsmyth Technologies Inc | Optical time delay apparatus incorporating diffractive element sets |
US7359597B1 (en) | 2004-08-23 | 2008-04-15 | Lightsmyth Technologies Inc | Birefringence control in planar optical waveguides |
US7120334B1 (en) | 2004-08-25 | 2006-10-10 | Lightsmyth Technologies Inc | Optical resonator formed in a planar optical waveguide with distributed optical structures |
US7330614B1 (en) | 2004-12-10 | 2008-02-12 | Lightsmyth Technologies Inc. | Integrated optical spectrometer incorporating sets of diffractive elements |
US7327908B1 (en) | 2005-03-07 | 2008-02-05 | Lightsmyth Technologies Inc. | Integrated optical sensor incorporating sets of diffractive elements |
US7349599B1 (en) | 2005-03-14 | 2008-03-25 | Lightsmyth Technologies Inc | Etched surface gratings fabricated using computed interference between simulated optical signals and reduction lithography |
US7643400B1 (en) | 2005-03-24 | 2010-01-05 | Lightsmyth Technologies Inc | Optical encoding of data with distributed diffractive structures |
US7190856B1 (en) | 2005-03-28 | 2007-03-13 | Lightsmyth Technologies Inc | Reconfigurable optical add-drop multiplexer incorporating sets of diffractive elements |
US8068709B2 (en) | 2005-09-12 | 2011-11-29 | Lightsmyth Technologies Inc. | Transmission gratings designed by computed interference between simulated optical signals and fabricated by reduction lithography |
US7639911B2 (en) * | 2005-12-08 | 2009-12-29 | Electronics And Telecommunications Research Institute | Optical device having optical waveguide including organic Bragg grating sheet |
GB0718706D0 (en) | 2007-09-25 | 2007-11-07 | Creative Physics Ltd | Method and apparatus for reducing laser speckle |
US7720334B1 (en) | 2006-07-07 | 2010-05-18 | Mossberg Thomas W | Laterally-confined holographic spectral filters |
US7773841B2 (en) * | 2006-10-19 | 2010-08-10 | Schlumberger Technology Corporation | Optical turnaround |
US20080102637A1 (en) * | 2006-10-31 | 2008-05-01 | Advanced Micro Devices, Inc. | Method and semiconductor structure for reliability characterization |
US7929190B2 (en) * | 2008-01-28 | 2011-04-19 | Vladimir Yankov | Integrated planar optical device based on digital planar holography |
US7616851B1 (en) * | 2008-06-26 | 2009-11-10 | Lockheed Martin Corporation | Tunable wavelength filter device |
US8774244B2 (en) | 2009-04-21 | 2014-07-08 | Daylight Solutions, Inc. | Thermal pointer |
US9335604B2 (en) | 2013-12-11 | 2016-05-10 | Milan Momcilo Popovich | Holographic waveguide display |
US11726332B2 (en) | 2009-04-27 | 2023-08-15 | Digilens Inc. | Diffractive projection apparatus |
US8233204B1 (en) | 2009-09-30 | 2012-07-31 | Rockwell Collins, Inc. | Optical displays |
US10795160B1 (en) | 2014-09-25 | 2020-10-06 | Rockwell Collins, Inc. | Systems for and methods of using fold gratings for dual axis expansion |
US11300795B1 (en) | 2009-09-30 | 2022-04-12 | Digilens Inc. | Systems for and methods of using fold gratings coordinated with output couplers for dual axis expansion |
US8451871B2 (en) | 2009-11-23 | 2013-05-28 | Vladimir Yankov | Method of manufacturing a laser diode with improved light-emitting characteristics |
US8085821B2 (en) | 2009-11-23 | 2011-12-27 | Vladimir Yankov | Light-enhancing device and method based on use of an optically active lasing medium in combination with digital planar holography |
US8659826B1 (en) | 2010-02-04 | 2014-02-25 | Rockwell Collins, Inc. | Worn display system and method without requiring real time tracking for boresight precision |
US8335413B2 (en) | 2010-05-14 | 2012-12-18 | Daylight Solutions, Inc. | Optical switch |
CN102386200B (en) * | 2010-08-27 | 2014-12-31 | 财团法人工业技术研究院 | Light emitting unit array and projection system |
US8467430B2 (en) | 2010-09-23 | 2013-06-18 | Daylight Solutions, Inc. | Continuous wavelength tunable laser source with optimum orientation of grating and gain medium |
US9225148B2 (en) | 2010-09-23 | 2015-12-29 | Daylight Solutions, Inc. | Laser source assembly with thermal control and mechanically stable mounting |
US9042688B2 (en) | 2011-01-26 | 2015-05-26 | Daylight Solutions, Inc. | Multiple port, multiple state optical switch |
WO2012136970A1 (en) | 2011-04-07 | 2012-10-11 | Milan Momcilo Popovich | Laser despeckler based on angular diversity |
US10670876B2 (en) | 2011-08-24 | 2020-06-02 | Digilens Inc. | Waveguide laser illuminator incorporating a despeckler |
WO2016020630A2 (en) | 2014-08-08 | 2016-02-11 | Milan Momcilo Popovich | Waveguide laser illuminator incorporating a despeckler |
WO2013027004A1 (en) | 2011-08-24 | 2013-02-28 | Milan Momcilo Popovich | Wearable data display |
US9366864B1 (en) | 2011-09-30 | 2016-06-14 | Rockwell Collins, Inc. | System for and method of displaying information without need for a combiner alignment detector |
US9507150B1 (en) | 2011-09-30 | 2016-11-29 | Rockwell Collins, Inc. | Head up display (HUD) using a bent waveguide assembly |
US9715067B1 (en) | 2011-09-30 | 2017-07-25 | Rockwell Collins, Inc. | Ultra-compact HUD utilizing waveguide pupil expander with surface relief gratings in high refractive index materials |
US8634139B1 (en) | 2011-09-30 | 2014-01-21 | Rockwell Collins, Inc. | System for and method of catadioptric collimation in a compact head up display (HUD) |
WO2013102759A2 (en) | 2012-01-06 | 2013-07-11 | Milan Momcilo Popovich | Contact image sensor using switchable bragg gratings |
US9523852B1 (en) | 2012-03-28 | 2016-12-20 | Rockwell Collins, Inc. | Micro collimator system and method for a head up display (HUD) |
EP2842003B1 (en) | 2012-04-25 | 2019-02-27 | Rockwell Collins, Inc. | Holographic wide angle display |
US9671566B2 (en) | 2012-06-11 | 2017-06-06 | Magic Leap, Inc. | Planar waveguide apparatus with diffraction element(s) and system employing same |
US8861057B2 (en) * | 2012-06-27 | 2014-10-14 | Ergophos, Llc | Speckle-reduced laser illumination device |
US9134479B2 (en) * | 2012-09-05 | 2015-09-15 | International Business Machines Corporation | Polarization diverse demultiplexing |
US9933684B2 (en) * | 2012-11-16 | 2018-04-03 | Rockwell Collins, Inc. | Transparent waveguide display providing upper and lower fields of view having a specific light output aperture configuration |
US9674413B1 (en) | 2013-04-17 | 2017-06-06 | Rockwell Collins, Inc. | Vision system and method having improved performance and solar mitigation |
US9952042B2 (en) | 2013-07-12 | 2018-04-24 | Magic Leap, Inc. | Method and system for identifying a user location |
WO2015006784A2 (en) | 2013-07-12 | 2015-01-15 | Magic Leap, Inc. | Planar waveguide apparatus with diffraction element(s) and system employing same |
US9727772B2 (en) | 2013-07-31 | 2017-08-08 | Digilens, Inc. | Method and apparatus for contact image sensing |
CN109445095B (en) | 2013-11-27 | 2021-11-23 | 奇跃公司 | Virtual and augmented reality systems and methods |
US10732407B1 (en) | 2014-01-10 | 2020-08-04 | Rockwell Collins, Inc. | Near eye head up display system and method with fixed combiner |
US9519089B1 (en) * | 2014-01-30 | 2016-12-13 | Rockwell Collins, Inc. | High performance volume phase gratings |
EP2908341B1 (en) * | 2014-02-18 | 2018-07-11 | ams AG | Semiconductor device with surface integrated focusing element |
US9244280B1 (en) | 2014-03-25 | 2016-01-26 | Rockwell Collins, Inc. | Near eye display system and method for display enhancement or redundancy |
WO2016020632A1 (en) | 2014-08-08 | 2016-02-11 | Milan Momcilo Popovich | Method for holographic mastering and replication |
US10241330B2 (en) | 2014-09-19 | 2019-03-26 | Digilens, Inc. | Method and apparatus for generating input images for holographic waveguide displays |
US10088675B1 (en) | 2015-05-18 | 2018-10-02 | Rockwell Collins, Inc. | Turning light pipe for a pupil expansion system and method |
US9715110B1 (en) | 2014-09-25 | 2017-07-25 | Rockwell Collins, Inc. | Automotive head up display (HUD) |
DE102014220141A1 (en) * | 2014-10-06 | 2016-04-07 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Light distributor, a system comprising a light distributor and at least one LED lamp and a method for producing a light distributor |
EP3245444B1 (en) | 2015-01-12 | 2021-09-08 | DigiLens Inc. | Environmentally isolated waveguide display |
US9632226B2 (en) | 2015-02-12 | 2017-04-25 | Digilens Inc. | Waveguide grating device |
US9618664B2 (en) * | 2015-04-15 | 2017-04-11 | Finisar Corporation | Partially etched phase-transforming optical element |
US10247943B1 (en) | 2015-05-18 | 2019-04-02 | Rockwell Collins, Inc. | Head up display (HUD) using a light pipe |
US10126552B2 (en) | 2015-05-18 | 2018-11-13 | Rockwell Collins, Inc. | Micro collimator system and method for a head up display (HUD) |
US11366316B2 (en) | 2015-05-18 | 2022-06-21 | Rockwell Collins, Inc. | Head up display (HUD) using a light pipe |
US10108010B2 (en) | 2015-06-29 | 2018-10-23 | Rockwell Collins, Inc. | System for and method of integrating head up displays and head down displays |
CA2996925C (en) * | 2015-09-05 | 2022-06-28 | Leia Inc. | Light concentrating backlight and near-eye display system using same |
US10690916B2 (en) | 2015-10-05 | 2020-06-23 | Digilens Inc. | Apparatus for providing waveguide displays with two-dimensional pupil expansion |
US10598932B1 (en) | 2016-01-06 | 2020-03-24 | Rockwell Collins, Inc. | Head up display for integrating views of conformally mapped symbols and a fixed image source |
US9864139B1 (en) * | 2016-01-22 | 2018-01-09 | Seagate Technology Llc | Uniform laser direct writing for waveguides |
US10288808B1 (en) | 2016-01-22 | 2019-05-14 | Seagate Technology Llc | Laser direct writing for non-linear waveguides |
JP6895451B2 (en) | 2016-03-24 | 2021-06-30 | ディジレンズ インコーポレイテッド | Methods and Devices for Providing Polarized Selective Holography Waveguide Devices |
US10815145B2 (en) | 2016-03-31 | 2020-10-27 | Corning Incorporated | High index glass and devices incorporating such |
JP6734933B2 (en) | 2016-04-11 | 2020-08-05 | ディジレンズ インコーポレイテッド | Holographic Waveguide Device for Structured Light Projection |
US10539723B2 (en) | 2016-10-19 | 2020-01-21 | Finisar Corporation | Phase-transforming optical reflector formed by partial etching or by partial etching with reflow |
WO2018102834A2 (en) | 2016-12-02 | 2018-06-07 | Digilens, Inc. | Waveguide device with uniform output illumination |
WO2018129398A1 (en) | 2017-01-05 | 2018-07-12 | Digilens, Inc. | Wearable heads up displays |
US10295824B2 (en) | 2017-01-26 | 2019-05-21 | Rockwell Collins, Inc. | Head up display with an angled light pipe |
CN106647042B (en) * | 2017-03-17 | 2018-11-06 | 京东方科技集团股份有限公司 | A kind of light source device and display device |
JP6844777B2 (en) * | 2017-04-28 | 2021-03-17 | 国立研究開発法人理化学研究所 | Holography reproduction method and program |
FR3066617A1 (en) * | 2017-05-17 | 2018-11-23 | Commissariat A L'energie Atomique Et Aux Energies Alternatives | PHOTONIC CHIP WITH REFLECTING STRUCTURE FOR OPTICAL PATH FOLDING |
JP7399084B2 (en) | 2017-10-16 | 2023-12-15 | ディジレンズ インコーポレイテッド | System and method for doubling the image resolution of pixelated displays |
CN111566571B (en) | 2018-01-08 | 2022-05-13 | 迪吉伦斯公司 | System and method for holographic grating high throughput recording in waveguide cells |
US10914950B2 (en) | 2018-01-08 | 2021-02-09 | Digilens Inc. | Waveguide architectures and related methods of manufacturing |
WO2020023779A1 (en) | 2018-07-25 | 2020-01-30 | Digilens Inc. | Systems and methods for fabricating a multilayer optical structure |
JP2022520472A (en) | 2019-02-15 | 2022-03-30 | ディジレンズ インコーポレイテッド | Methods and equipment for providing holographic waveguide displays using integrated grids |
US20200292745A1 (en) | 2019-03-12 | 2020-09-17 | Digilens Inc. | Holographic Waveguide Backlight and Related Methods of Manufacturing |
JP2022535460A (en) | 2019-06-07 | 2022-08-08 | ディジレンズ インコーポレイテッド | Waveguides incorporating transmission and reflection gratings, and associated fabrication methods |
JP2022543571A (en) | 2019-07-29 | 2022-10-13 | ディジレンズ インコーポレイテッド | Method and Apparatus for Multiplying Image Resolution and Field of View for Pixelated Displays |
US11442222B2 (en) | 2019-08-29 | 2022-09-13 | Digilens Inc. | Evacuated gratings and methods of manufacturing |
CN114236688B (en) * | 2021-11-23 | 2023-09-19 | 中国电子科技集团公司第三十八研究所 | Multimode waveguide chirped Bragg grating delay line chip with even-numbered highest order |
Citations (80)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US602242A (en) * | 1898-04-12 | Air-indicator for bicycle-tires | ||
US4006967A (en) * | 1975-04-23 | 1977-02-08 | Battelle Memorial Institute | Directing optical beam |
US4140362A (en) * | 1977-07-14 | 1979-02-20 | Bell Telephone Laboratories, Incorporated | Forming focusing diffraction gratings for integrated optics |
US4387955A (en) * | 1981-02-03 | 1983-06-14 | The United States Of America As Represented By The Secretary Of The Air Force | Holographic reflective grating multiplexer/demultiplexer |
US4440468A (en) * | 1980-09-23 | 1984-04-03 | Siemens Aktiengesellschaft | Planar waveguide bragg lens and its utilization |
US4660934A (en) * | 1984-03-21 | 1987-04-28 | Kokusai Denshin Denwa Kabushiki Kaisha | Method for manufacturing diffraction grating |
US4740951A (en) * | 1985-03-13 | 1988-04-26 | Commissariat A L'energie Atomique | Reversible device for the demultiplexing of several light signals in integrated optics |
US4743083A (en) * | 1985-12-30 | 1988-05-10 | Schimpe Robert M | Cylindrical diffraction grating couplers and distributed feedback resonators for guided wave devices |
US4746186A (en) * | 1983-12-15 | 1988-05-24 | U.S. Philips Corp. | Integrated optical multiplexer/demultiplexer utilizing a plurality of blazed gratings |
US4773063A (en) * | 1984-11-13 | 1988-09-20 | University Of Delaware | Optical wavelength division multiplexing/demultiplexing system |
US4803696A (en) * | 1987-06-30 | 1989-02-07 | Hughes Aircraft Company | Laser with grating feedback unstable resonator |
US4824193A (en) * | 1985-07-26 | 1989-04-25 | Matsushita Electric Industrial Co., Ltd. | Holographic multiplexer/demultiplexer and its manufacturing method |
US4834474A (en) * | 1987-05-01 | 1989-05-30 | The University Of Rochester | Optical systems using volume holographic elements to provide arbitrary space-time characteristics, including frequency-and/or spatially-dependent delay lines, chirped pulse compressors, pulse hirpers, pulse shapers, and laser resonators |
US4846552A (en) * | 1986-04-16 | 1989-07-11 | The United States Of America As Represented By The Secretary Of The Air Force | Method of fabricating high efficiency binary planar optical elements |
US4852960A (en) * | 1987-03-11 | 1989-08-01 | American Telephone And Telegraph Company, At&T Bell Laboratories | Narrow-linewidth resonant optical device, transmitter, system, and method |
US4923271A (en) * | 1989-03-28 | 1990-05-08 | American Telephone And Telegraph Company | Optical multiplexer/demultiplexer using focusing Bragg reflectors |
US4938553A (en) * | 1987-03-16 | 1990-07-03 | Siemens Aktiengesellschaft | Arrangement for an integrated optical spectrometer and the method for manufacturing the spectrometer |
US5040864A (en) * | 1990-11-13 | 1991-08-20 | Rockwell International Corporation | Optical crosspoint switch module |
US5042898A (en) * | 1989-12-26 | 1991-08-27 | United Technologies Corporation | Incorporated Bragg filter temperature compensated optical waveguide device |
US5093874A (en) * | 1991-04-01 | 1992-03-03 | Eastman Kodak Company | Integrated electro-optical scanner with photoconductive substrate |
US5107359A (en) * | 1988-11-25 | 1992-04-21 | Ricoh Company, Ltd. | Optical wavelength-divison multi/demultiplexer |
US5195161A (en) * | 1991-12-11 | 1993-03-16 | At&T Bell Laboratories | Optical waveguide comprising Bragg grating coupling means |
US5357591A (en) * | 1993-04-06 | 1994-10-18 | Yuan Jiang | Cylindrical-wave controlling, generating and guiding devices |
US5450511A (en) * | 1992-04-29 | 1995-09-12 | At&T Corp. | Efficient reflective multiplexer arrangement |
US5453871A (en) * | 1989-06-14 | 1995-09-26 | Hewlett-Packard Company | Temporal imaging with a time lens |
US5668900A (en) * | 1995-11-01 | 1997-09-16 | Northern Telecom Limited | Taper shapes for sidelobe suppression and bandwidth minimization in distributed feedback optical reflection filters |
US5768450A (en) * | 1996-01-11 | 1998-06-16 | Corning Incorporated | Wavelength multiplexer/demultiplexer with varied propagation constant |
US5812318A (en) * | 1995-03-13 | 1998-09-22 | University Of Washington | Apparatus and methods for routing of optical beams via time-domain spatial-spectral filtering |
US5887094A (en) * | 1996-09-02 | 1999-03-23 | Alcatel Alsthom Compagnie Generale D'electricite | Band-pass filter in an optical waveguide |
US5907547A (en) * | 1996-10-24 | 1999-05-25 | At&T Corp | System and method for establishing internet communications links |
US6011884A (en) * | 1997-12-13 | 2000-01-04 | Lightchip, Inc. | Integrated bi-directional axial gradient refractive index/diffraction grating wavelength division multiplexer |
US6011885A (en) * | 1997-12-13 | 2000-01-04 | Lightchip, Inc. | Integrated bi-directional gradient refractive index wavelength division multiplexer |
US6137933A (en) * | 1997-12-13 | 2000-10-24 | Lightchip, Inc. | Integrated bi-directional dual axial gradient refractive index/diffraction grating wavelength division multiplexer |
US6169614B1 (en) * | 1999-05-21 | 2001-01-02 | Psc Scanning, Inc. | Wedged-shape holographic collector |
US6169613B1 (en) * | 1993-02-26 | 2001-01-02 | Yeda Research & Devel Co., Ltd. | Planar holographic optical device for beam expansion and display |
US6243514B1 (en) * | 1998-02-13 | 2001-06-05 | Nortel Networks Limited | Optical multiplexer/demultiplexer |
US6266463B1 (en) * | 1997-06-18 | 2001-07-24 | Pirelli Cavi E Sistemi S.P.A. | Chirped optical fibre grating |
US6285813B1 (en) * | 1997-10-03 | 2001-09-04 | Georgia Tech Research Corporation | Diffractive grating coupler and method |
US20020071646A1 (en) * | 2000-12-08 | 2002-06-13 | Eggleton Benjamin John | Waveguide incorporating tunable scattering material |
US6408118B1 (en) * | 2000-08-25 | 2002-06-18 | Agere Systems Guardian Corp. | Optical waveguide gratings having roughened cladding for reduced short wavelength cladding mode loss |
US6473232B2 (en) * | 2000-03-08 | 2002-10-29 | Canon Kabushiki Kaisha | Optical system having a diffractive optical element, and optical apparatus |
US20030011833A1 (en) * | 2001-04-26 | 2003-01-16 | Vladimir Yankov | Planar holographic multiplexer/demultiplexer |
US20030039444A1 (en) * | 2001-08-27 | 2003-02-27 | Mossberg Thomas W. | Amplitude and phase control in distributed optical structures |
US20030068113A1 (en) * | 2001-09-12 | 2003-04-10 | Siegfried Janz | Method for polarization birefringence compensation in a waveguide demultiplexer using a compensator with a high refractive index capping layer. |
US20030067645A1 (en) * | 2001-08-27 | 2003-04-10 | Adc Denmark Aps. | Wavelength division multiplexed device |
US6553162B1 (en) * | 1999-11-16 | 2003-04-22 | Oki Electric Industry Co., Ltd. | Optical multiplexer-demultiplexer with mutually intersecting sub-gratings |
US20030117677A1 (en) * | 2000-03-16 | 2003-06-26 | Mossberg Thomas W. | Optical processor |
US6603901B1 (en) * | 2000-03-03 | 2003-08-05 | Lucent Technologies Inc. | Optical fiber gratings with index matched polymer coating for cladding mode suppression |
US20030185269A1 (en) * | 2002-03-26 | 2003-10-02 | Gutin Mikhail A. | Fiber-coupled vertical-cavity surface emitting laser |
US6702897B2 (en) * | 1999-03-25 | 2004-03-09 | Acme Grating Ventures, Llc | Optical transmission systems and apparatuses including bragg gratings and methods of making |
US20040047561A1 (en) * | 2000-12-28 | 2004-03-11 | Hiroyuki Tuda | Optical signal processing circuit and method of producing same |
US6718093B2 (en) * | 2000-11-27 | 2004-04-06 | Advanced Interfaces, Llc | Integrated optical multiplexer and demultiplexer for wavelength division transmission of information |
US20040076374A1 (en) * | 2001-08-27 | 2004-04-22 | Greiner Christoph M. | Amplitude and phase control in distributed optical structures |
US20040131360A1 (en) * | 2002-12-17 | 2004-07-08 | Dmitri Iazikov | Optical multiplexing device |
US6768834B1 (en) * | 2003-06-13 | 2004-07-27 | Agilent Technologies, Inc. | Slab optical multiplexer |
US6781944B1 (en) * | 1999-02-25 | 2004-08-24 | Hitachi, Ltd. | Optical information processor with monolithically integrated light emitting device, light receiving devices and optics |
US20040170356A1 (en) * | 2000-03-16 | 2004-09-02 | Dmitri Iazikov | Temperature-compensated planar waveguide optical apparatus |
US20040173680A1 (en) * | 2003-03-04 | 2004-09-09 | Mossberg Thomas W. | Spectrally-encoded labeling and reading |
US20040179779A1 (en) * | 2003-03-10 | 2004-09-16 | Greiner Christoph M. | Optical structures distributed among multiple optical waveguides |
US20040208466A1 (en) * | 2000-03-16 | 2004-10-21 | Mossberg Thomas W. | Multimode planar waveguide spectral filter |
US20050018951A1 (en) * | 2000-03-16 | 2005-01-27 | Mossberg Thomas W. | Multiple-wavelength optical source |
US6850670B2 (en) * | 2001-06-28 | 2005-02-01 | Lightwave Microsytstems Corporation | Method and apparatus for controlling waveguide birefringence by selection of a waveguide core width for a top clad |
US6859318B1 (en) * | 2000-03-16 | 2005-02-22 | Thomas W. Mossberg | Method for forming a holographic spectral filter |
US20050063430A1 (en) * | 2003-09-18 | 2005-03-24 | Universite Laval | Multi-wave length laser source |
US6876791B2 (en) * | 2001-09-03 | 2005-04-05 | Sumitomo Electric Industries, Ltd. | Diffraction grating device |
US20050078912A1 (en) * | 2000-03-16 | 2005-04-14 | Dmitri Iazikov | Distributed optical structures with improved diffraction efficiency and/or improved optical coupling |
US20050135747A1 (en) * | 2000-03-16 | 2005-06-23 | Greiner Christoph M. | Multiple distributed optical structures in a single optical element |
US20050163425A1 (en) * | 2000-03-16 | 2005-07-28 | Greiner Christoph M. | Distributed optical structures designed by computed interference between simulated optical signals |
US6928223B2 (en) * | 2000-07-14 | 2005-08-09 | Massachusetts Institute Of Technology | Stab-coupled optical waveguide laser and amplifier |
US20050196114A1 (en) * | 2004-02-25 | 2005-09-08 | National Research Council Of Canada | Stress-induced control of polarization dependent properties in photonic devices |
US6990276B2 (en) * | 2000-03-16 | 2006-01-24 | Lightsmyth Technologies, Inc. | Optical waveform recognition and/or generation and optical switching |
US7003187B2 (en) * | 2000-08-07 | 2006-02-21 | Rosemount Inc. | Optical switch with moveable holographic optical element |
US7016569B2 (en) * | 2002-07-31 | 2006-03-21 | Georgia Tech Research Corporation | Back-side-of-die, through-wafer guided-wave optical clock distribution networks, method of fabrication thereof, and uses thereof |
US7049704B2 (en) * | 2001-06-26 | 2006-05-23 | Intel Corporation | Flip-chip package integrating optical and electrical devices and coupling to a waveguide on a board |
US20060177178A1 (en) * | 2001-08-27 | 2006-08-10 | Greiner Christoph M | Amplitude and phase control in distributed optical structures |
US20060210214A1 (en) * | 2005-03-15 | 2006-09-21 | Uhlhorn Brian L | Integrated volume holographic optical circuit apparatus |
US7181103B1 (en) * | 2004-02-20 | 2007-02-20 | Lightsmyth Technologies Inc | Optical interconnect structures incorporating sets of diffractive elements |
US7194161B1 (en) * | 1999-06-30 | 2007-03-20 | The Regents Of The University Of California | Wavelength-conserving grating router for intermediate wavelength density |
US7209611B2 (en) * | 2002-10-08 | 2007-04-24 | Infinera Corporation | Transmitter photonic integrated circuit (TxPIC) chips utilizing compact wavelength selective combiners/decombiners |
US7260290B1 (en) * | 2003-12-24 | 2007-08-21 | Lightsmyth Technologies Inc | Distributed optical structures exhibiting reduced optical loss |
Family Cites Families (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2442652A1 (en) | 1974-09-06 | 1976-03-18 | Siemens Ag | ARRANGEMENT FOR TUNABLE OPTICAL WAVE CONDUCTOR COMPONENTS |
GB8431087D0 (en) | 1984-12-10 | 1985-01-16 | Secr Defence | Multiplexing & demultiplexing systems |
FR2609180B1 (en) | 1986-12-31 | 1989-11-03 | Commissariat Energie Atomique | MULTIPLEXER-DEMULTIPLEXER USING A CONCAVE ELLIPTICAL NETWORK AND CONDUCTED IN INTEGRATED OPTICS |
GB8723050D0 (en) | 1987-10-01 | 1987-11-04 | British Telecomm | Optical filters |
AT393183B (en) | 1987-12-15 | 1991-08-26 | Avl Verbrennungskraft Messtech | PIEZOELECTRIC CRYSTAL ELEMENT AND METHOD FOR PRODUCING THE SAME |
US5165104A (en) | 1991-03-01 | 1992-11-17 | Optivideo Corporation | Optical interconnecting device and method |
JP2755504B2 (en) | 1991-06-10 | 1998-05-20 | 松下電器産業株式会社 | Phase-locked semiconductor laser |
JP3033805B2 (en) | 1993-09-20 | 2000-04-17 | 株式会社富士通ゼネラル | Method of forming via hole in thick film IC |
AUPM386794A0 (en) | 1994-02-14 | 1994-03-10 | University Of Sydney, The | Optical grating |
SE9600758D0 (en) | 1996-02-28 | 1996-02-28 | Forskarpatent I Goeteborg Ab | Hologram |
US5907647A (en) | 1997-02-18 | 1999-05-25 | Lucent Technologies Inc. | Long-period grating switches and devices using them |
JPH1195033A (en) | 1997-07-23 | 1999-04-09 | Sumitomo Electric Ind Ltd | Grating band-pass filter, and manufacture thereof |
JP3152189B2 (en) | 1997-12-04 | 2001-04-03 | 日立電線株式会社 | Planar waveguide grating element |
KR20010033934A (en) | 1998-01-07 | 2001-04-25 | 마이클 디. 존스 | Composite diffraction gratings for signal processing and optical control applications |
WO1999056159A1 (en) | 1998-04-24 | 1999-11-04 | Templex Technology Inc. | Segmented complex diffraction gratings |
US6323970B1 (en) | 1999-09-29 | 2001-11-27 | Digilents, Inc. | Method of producing switchable holograms |
JP4749617B2 (en) | 2001-07-23 | 2011-08-17 | 三菱電機株式会社 | Strip connection device |
JP3895166B2 (en) | 2001-12-17 | 2007-03-22 | 大日本印刷株式会社 | How to create a computer generated hologram |
JP3947406B2 (en) | 2002-02-15 | 2007-07-18 | 株式会社ルネサステクノロジ | Semiconductor laser module |
US20030206694A1 (en) | 2002-05-02 | 2003-11-06 | Vyoptics, Inc. | Photonic multi-bandgap lightwave device and methods for manufacturing thereof |
EP1649564A4 (en) | 2003-07-03 | 2007-09-05 | Pd Ld Inc | Use of volume bragg gratings for the conditioning of laser emission characteristics |
US7120334B1 (en) | 2004-08-25 | 2006-10-10 | Lightsmyth Technologies Inc | Optical resonator formed in a planar optical waveguide with distributed optical structures |
-
2004
- 2004-05-11 US US10/842,790 patent/US6987911B2/en not_active Expired - Fee Related
-
2006
- 2006-01-17 US US11/334,039 patent/US7499612B2/en not_active Expired - Fee Related
-
2009
- 2009-02-06 US US12/367,159 patent/US7742674B2/en not_active Expired - Fee Related
-
2010
- 2010-05-24 US US12/785,950 patent/US8180188B2/en not_active Expired - Fee Related
Patent Citations (100)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US602242A (en) * | 1898-04-12 | Air-indicator for bicycle-tires | ||
US4006967A (en) * | 1975-04-23 | 1977-02-08 | Battelle Memorial Institute | Directing optical beam |
US4140362A (en) * | 1977-07-14 | 1979-02-20 | Bell Telephone Laboratories, Incorporated | Forming focusing diffraction gratings for integrated optics |
US4440468A (en) * | 1980-09-23 | 1984-04-03 | Siemens Aktiengesellschaft | Planar waveguide bragg lens and its utilization |
US4387955A (en) * | 1981-02-03 | 1983-06-14 | The United States Of America As Represented By The Secretary Of The Air Force | Holographic reflective grating multiplexer/demultiplexer |
US4746186A (en) * | 1983-12-15 | 1988-05-24 | U.S. Philips Corp. | Integrated optical multiplexer/demultiplexer utilizing a plurality of blazed gratings |
US4660934A (en) * | 1984-03-21 | 1987-04-28 | Kokusai Denshin Denwa Kabushiki Kaisha | Method for manufacturing diffraction grating |
US4773063A (en) * | 1984-11-13 | 1988-09-20 | University Of Delaware | Optical wavelength division multiplexing/demultiplexing system |
US4740951A (en) * | 1985-03-13 | 1988-04-26 | Commissariat A L'energie Atomique | Reversible device for the demultiplexing of several light signals in integrated optics |
US4824193A (en) * | 1985-07-26 | 1989-04-25 | Matsushita Electric Industrial Co., Ltd. | Holographic multiplexer/demultiplexer and its manufacturing method |
US4743083A (en) * | 1985-12-30 | 1988-05-10 | Schimpe Robert M | Cylindrical diffraction grating couplers and distributed feedback resonators for guided wave devices |
US4846552A (en) * | 1986-04-16 | 1989-07-11 | The United States Of America As Represented By The Secretary Of The Air Force | Method of fabricating high efficiency binary planar optical elements |
US4852960A (en) * | 1987-03-11 | 1989-08-01 | American Telephone And Telegraph Company, At&T Bell Laboratories | Narrow-linewidth resonant optical device, transmitter, system, and method |
US4938553A (en) * | 1987-03-16 | 1990-07-03 | Siemens Aktiengesellschaft | Arrangement for an integrated optical spectrometer and the method for manufacturing the spectrometer |
US4834474A (en) * | 1987-05-01 | 1989-05-30 | The University Of Rochester | Optical systems using volume holographic elements to provide arbitrary space-time characteristics, including frequency-and/or spatially-dependent delay lines, chirped pulse compressors, pulse hirpers, pulse shapers, and laser resonators |
US4803696A (en) * | 1987-06-30 | 1989-02-07 | Hughes Aircraft Company | Laser with grating feedback unstable resonator |
US5107359A (en) * | 1988-11-25 | 1992-04-21 | Ricoh Company, Ltd. | Optical wavelength-divison multi/demultiplexer |
US4923271A (en) * | 1989-03-28 | 1990-05-08 | American Telephone And Telegraph Company | Optical multiplexer/demultiplexer using focusing Bragg reflectors |
US5453871A (en) * | 1989-06-14 | 1995-09-26 | Hewlett-Packard Company | Temporal imaging with a time lens |
US5042898A (en) * | 1989-12-26 | 1991-08-27 | United Technologies Corporation | Incorporated Bragg filter temperature compensated optical waveguide device |
US5040864A (en) * | 1990-11-13 | 1991-08-20 | Rockwell International Corporation | Optical crosspoint switch module |
US5093874A (en) * | 1991-04-01 | 1992-03-03 | Eastman Kodak Company | Integrated electro-optical scanner with photoconductive substrate |
US5195161A (en) * | 1991-12-11 | 1993-03-16 | At&T Bell Laboratories | Optical waveguide comprising Bragg grating coupling means |
US5450511A (en) * | 1992-04-29 | 1995-09-12 | At&T Corp. | Efficient reflective multiplexer arrangement |
US6169613B1 (en) * | 1993-02-26 | 2001-01-02 | Yeda Research & Devel Co., Ltd. | Planar holographic optical device for beam expansion and display |
US5357591A (en) * | 1993-04-06 | 1994-10-18 | Yuan Jiang | Cylindrical-wave controlling, generating and guiding devices |
US5812318A (en) * | 1995-03-13 | 1998-09-22 | University Of Washington | Apparatus and methods for routing of optical beams via time-domain spatial-spectral filtering |
US5668900A (en) * | 1995-11-01 | 1997-09-16 | Northern Telecom Limited | Taper shapes for sidelobe suppression and bandwidth minimization in distributed feedback optical reflection filters |
US5768450A (en) * | 1996-01-11 | 1998-06-16 | Corning Incorporated | Wavelength multiplexer/demultiplexer with varied propagation constant |
US5887094A (en) * | 1996-09-02 | 1999-03-23 | Alcatel Alsthom Compagnie Generale D'electricite | Band-pass filter in an optical waveguide |
US5907547A (en) * | 1996-10-24 | 1999-05-25 | At&T Corp | System and method for establishing internet communications links |
US6266463B1 (en) * | 1997-06-18 | 2001-07-24 | Pirelli Cavi E Sistemi S.P.A. | Chirped optical fibre grating |
US6285813B1 (en) * | 1997-10-03 | 2001-09-04 | Georgia Tech Research Corporation | Diffractive grating coupler and method |
US6137933A (en) * | 1997-12-13 | 2000-10-24 | Lightchip, Inc. | Integrated bi-directional dual axial gradient refractive index/diffraction grating wavelength division multiplexer |
US6011885A (en) * | 1997-12-13 | 2000-01-04 | Lightchip, Inc. | Integrated bi-directional gradient refractive index wavelength division multiplexer |
US6011884A (en) * | 1997-12-13 | 2000-01-04 | Lightchip, Inc. | Integrated bi-directional axial gradient refractive index/diffraction grating wavelength division multiplexer |
US6243514B1 (en) * | 1998-02-13 | 2001-06-05 | Nortel Networks Limited | Optical multiplexer/demultiplexer |
US6781944B1 (en) * | 1999-02-25 | 2004-08-24 | Hitachi, Ltd. | Optical information processor with monolithically integrated light emitting device, light receiving devices and optics |
US6702897B2 (en) * | 1999-03-25 | 2004-03-09 | Acme Grating Ventures, Llc | Optical transmission systems and apparatuses including bragg gratings and methods of making |
US6169614B1 (en) * | 1999-05-21 | 2001-01-02 | Psc Scanning, Inc. | Wedged-shape holographic collector |
US7194161B1 (en) * | 1999-06-30 | 2007-03-20 | The Regents Of The University Of California | Wavelength-conserving grating router for intermediate wavelength density |
US6553162B1 (en) * | 1999-11-16 | 2003-04-22 | Oki Electric Industry Co., Ltd. | Optical multiplexer-demultiplexer with mutually intersecting sub-gratings |
US6603901B1 (en) * | 2000-03-03 | 2003-08-05 | Lucent Technologies Inc. | Optical fiber gratings with index matched polymer coating for cladding mode suppression |
US6473232B2 (en) * | 2000-03-08 | 2002-10-29 | Canon Kabushiki Kaisha | Optical system having a diffractive optical element, and optical apparatus |
US7054517B2 (en) * | 2000-03-16 | 2006-05-30 | Lightsmyth Technologies Inc | Multiple-wavelength optical source |
US6990276B2 (en) * | 2000-03-16 | 2006-01-24 | Lightsmyth Technologies, Inc. | Optical waveform recognition and/or generation and optical switching |
US20030117677A1 (en) * | 2000-03-16 | 2003-06-26 | Mossberg Thomas W. | Optical processor |
US20060233493A1 (en) * | 2000-03-16 | 2006-10-19 | Lightsmyth Technologies Inc. | Holographic spectral filter |
US20060139712A1 (en) * | 2000-03-16 | 2006-06-29 | Mossberg Thomas W | Optical processor |
US7062128B2 (en) * | 2000-03-16 | 2006-06-13 | Lightsmyth Technologies Inc | Holographic spectral filter |
US7190859B2 (en) * | 2000-03-16 | 2007-03-13 | Lightsmyth Technologies Inc | Distributed optical structures in a planar waveguide coupling in-plane and out-of-plane optical signals |
US20050078912A1 (en) * | 2000-03-16 | 2005-04-14 | Dmitri Iazikov | Distributed optical structures with improved diffraction efficiency and/or improved optical coupling |
US7009743B2 (en) * | 2000-03-16 | 2006-03-07 | Lightsmyth Technologies Inc | Optical processor |
US20060023280A1 (en) * | 2000-03-16 | 2006-02-02 | Mossberg Thomas W | Optical processor |
US6993223B2 (en) * | 2000-03-16 | 2006-01-31 | Lightsmyth Technologies, Inc. | Multiple distributed optical structures in a single optical element |
US20060193553A1 (en) * | 2000-03-16 | 2006-08-31 | Lightsmyth Technologies Inc | Multiple wavelength optical source |
US7194164B2 (en) * | 2000-03-16 | 2007-03-20 | Lightsmyth Technologies Inc | Distributed optical structures with improved diffraction efficiency and/or improved optical coupling |
US20040170356A1 (en) * | 2000-03-16 | 2004-09-02 | Dmitri Iazikov | Temperature-compensated planar waveguide optical apparatus |
US6987911B2 (en) * | 2000-03-16 | 2006-01-17 | Lightsmyth Technologies, Inc. | Multimode planar waveguide spectral filter |
US6985656B2 (en) * | 2000-03-16 | 2006-01-10 | Lightsmyth Technologies Inc | Temperature-compensated planar waveguide optical apparatus |
US20040208466A1 (en) * | 2000-03-16 | 2004-10-21 | Mossberg Thomas W. | Multimode planar waveguide spectral filter |
US7499612B2 (en) * | 2000-03-16 | 2009-03-03 | Mossberg Thomas W | Multimode planar waveguide spectral filter |
US20050018951A1 (en) * | 2000-03-16 | 2005-01-27 | Mossberg Thomas W. | Multiple-wavelength optical source |
US20050163425A1 (en) * | 2000-03-16 | 2005-07-28 | Greiner Christoph M. | Distributed optical structures designed by computed interference between simulated optical signals |
US6859318B1 (en) * | 2000-03-16 | 2005-02-22 | Thomas W. Mossberg | Method for forming a holographic spectral filter |
US20050152011A1 (en) * | 2000-03-16 | 2005-07-14 | Mossberg Thomas W. | Holographic spectral filter |
US20050135747A1 (en) * | 2000-03-16 | 2005-06-23 | Greiner Christoph M. | Multiple distributed optical structures in a single optical element |
US6879441B1 (en) * | 2000-03-16 | 2005-04-12 | Thomas Mossberg | Holographic spectral filter |
US6928223B2 (en) * | 2000-07-14 | 2005-08-09 | Massachusetts Institute Of Technology | Stab-coupled optical waveguide laser and amplifier |
US7003187B2 (en) * | 2000-08-07 | 2006-02-21 | Rosemount Inc. | Optical switch with moveable holographic optical element |
US6408118B1 (en) * | 2000-08-25 | 2002-06-18 | Agere Systems Guardian Corp. | Optical waveguide gratings having roughened cladding for reduced short wavelength cladding mode loss |
US6718093B2 (en) * | 2000-11-27 | 2004-04-06 | Advanced Interfaces, Llc | Integrated optical multiplexer and demultiplexer for wavelength division transmission of information |
US20020071646A1 (en) * | 2000-12-08 | 2002-06-13 | Eggleton Benjamin John | Waveguide incorporating tunable scattering material |
US20040047561A1 (en) * | 2000-12-28 | 2004-03-11 | Hiroyuki Tuda | Optical signal processing circuit and method of producing same |
US20030011833A1 (en) * | 2001-04-26 | 2003-01-16 | Vladimir Yankov | Planar holographic multiplexer/demultiplexer |
US7049704B2 (en) * | 2001-06-26 | 2006-05-23 | Intel Corporation | Flip-chip package integrating optical and electrical devices and coupling to a waveguide on a board |
US6850670B2 (en) * | 2001-06-28 | 2005-02-01 | Lightwave Microsytstems Corporation | Method and apparatus for controlling waveguide birefringence by selection of a waveguide core width for a top clad |
US20030067645A1 (en) * | 2001-08-27 | 2003-04-10 | Adc Denmark Aps. | Wavelength division multiplexed device |
US20050135744A1 (en) * | 2001-08-27 | 2005-06-23 | Greiner Christoph M. | Amplitude and phase control in distributed optical structures |
US20060177178A1 (en) * | 2001-08-27 | 2006-08-10 | Greiner Christoph M | Amplitude and phase control in distributed optical structures |
US20040076374A1 (en) * | 2001-08-27 | 2004-04-22 | Greiner Christoph M. | Amplitude and phase control in distributed optical structures |
US20030039444A1 (en) * | 2001-08-27 | 2003-02-27 | Mossberg Thomas W. | Amplitude and phase control in distributed optical structures |
US6678429B2 (en) * | 2001-08-27 | 2004-01-13 | Lightsmyth Technologies, Inc. | Amplitude and phase control in distributed optical structures |
US6876791B2 (en) * | 2001-09-03 | 2005-04-05 | Sumitomo Electric Industries, Ltd. | Diffraction grating device |
US20030068113A1 (en) * | 2001-09-12 | 2003-04-10 | Siegfried Janz | Method for polarization birefringence compensation in a waveguide demultiplexer using a compensator with a high refractive index capping layer. |
US20030185269A1 (en) * | 2002-03-26 | 2003-10-02 | Gutin Mikhail A. | Fiber-coupled vertical-cavity surface emitting laser |
US7016569B2 (en) * | 2002-07-31 | 2006-03-21 | Georgia Tech Research Corporation | Back-side-of-die, through-wafer guided-wave optical clock distribution networks, method of fabrication thereof, and uses thereof |
US7209611B2 (en) * | 2002-10-08 | 2007-04-24 | Infinera Corporation | Transmitter photonic integrated circuit (TxPIC) chips utilizing compact wavelength selective combiners/decombiners |
US20040131360A1 (en) * | 2002-12-17 | 2004-07-08 | Dmitri Iazikov | Optical multiplexing device |
US7224855B2 (en) * | 2002-12-17 | 2007-05-29 | Lightsmyth Technologies Inc. | Optical multiplexing device |
US20040173680A1 (en) * | 2003-03-04 | 2004-09-09 | Mossberg Thomas W. | Spectrally-encoded labeling and reading |
US20040179779A1 (en) * | 2003-03-10 | 2004-09-16 | Greiner Christoph M. | Optical structures distributed among multiple optical waveguides |
US6823115B2 (en) * | 2003-03-10 | 2004-11-23 | Christoph M. Greiner | Optical structures distributed among multiple optical waveguides |
US20050135745A1 (en) * | 2003-03-10 | 2005-06-23 | Greiner Christoph M. | Optical structures distributed among multiple optical waveguides |
US6768834B1 (en) * | 2003-06-13 | 2004-07-27 | Agilent Technologies, Inc. | Slab optical multiplexer |
US20050063430A1 (en) * | 2003-09-18 | 2005-03-24 | Universite Laval | Multi-wave length laser source |
US7260290B1 (en) * | 2003-12-24 | 2007-08-21 | Lightsmyth Technologies Inc | Distributed optical structures exhibiting reduced optical loss |
US7181103B1 (en) * | 2004-02-20 | 2007-02-20 | Lightsmyth Technologies Inc | Optical interconnect structures incorporating sets of diffractive elements |
US20050196114A1 (en) * | 2004-02-25 | 2005-09-08 | National Research Council Of Canada | Stress-induced control of polarization dependent properties in photonic devices |
US20060210214A1 (en) * | 2005-03-15 | 2006-09-21 | Uhlhorn Brian L | Integrated volume holographic optical circuit apparatus |
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US20130265624A1 (en) * | 2012-04-05 | 2013-10-10 | Oracle International Corporation | Surface-normal optical coupling using a holographic recording material |
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Also Published As
Publication number | Publication date |
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US7499612B2 (en) | 2009-03-03 |
US20090196551A1 (en) | 2009-08-06 |
US20040208466A1 (en) | 2004-10-21 |
US6987911B2 (en) | 2006-01-17 |
US20070034730A1 (en) | 2007-02-15 |
US7742674B2 (en) | 2010-06-22 |
US8180188B2 (en) | 2012-05-15 |
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